Email Deliverability Checklist: Fix Spam Folder Problems in 30 Minutes (2026)

If your newsletters are landing in spam, better subject lines will not save them. People cannot open emails they never really see.

This guide gives you a practical checklist you can run in about 30 minutes to find the most common causes of spam-folder placement and fix the highest-impact issues first. It focuses on the levers you control right now: authentication, list hygiene, content, cadence, and sender reputation.

One quick reality check: no checklist can guarantee inbox placement. Gmail, Yahoo, Outlook, and other providers use proprietary filters and recipient-level engagement data. But you can spot likely causes, remove obvious trust issues, and avoid making the problem worse.

A simple order helps:

Authenticate first, prune second, segment third, then review content and cadence.

---

What this checklist helps you fix

The difference between delivery, deliverability, and inbox placement

These terms often get used interchangeably, but they mean different things:

• Delivery: the receiving mail server accepted your message.
• Deliverability: your ability to reach the inbox consistently over time.
• Inbox placement: where the message ends up after delivery, such as inbox, promotions, updates, or spam.

So yes, a message can be delivered and still fail if it lands in spam.

A common example:

• Your ESP says 99% delivered
• Open rates drop sharply
• Gmail users stop engaging
• Test addresses show the newsletter in spam

That is not a delivery issue. It is an inbox placement issue.

What you can realistically improve in 30 minutes

In half an hour, you can usually:

• Confirm whether the problem is broad or isolated
• Check whether SPF, DKIM, and DMARC are present and aligned
• Spot obvious DNS mistakes
• Review bounce, complaint, and unsubscribe trends
• Identify risky list sources
• Suppress hard bounces and likely dead weight before your next send
• Compare performance across Gmail, Yahoo, and Microsoft inboxes
• Catch suspicious links, redirect chains, or recent subject-line changes
• Standardize your From identity
• Avoid a premature platform switch

What you usually cannot do in 30 minutes:

• Repair damaged sender reputation overnight
• Warm up a brand-new domain instantly
• Undo a month of poor list practices with one technical fix
• Force every provider to place your mail in the inbox

When this checklist is the right solution—and when it is not

This checklist is a good fit when:

• Your newsletters suddenly start going to spam
• Opens or clicks drop without a clear reason
• You changed ESP settings, domains, or templates recently
• You imported a new segment and performance collapsed
• Gmail or Outlook got worse while other providers stayed stable
• Transactional emails still work, but marketing emails struggle

This checklist is not enough on its own when:

• Your domain has a long history of poor sending practices
• You send at very high volume and need provider-specific remediation
• Your organization uses complex sending infrastructure across multiple tools
• A dedicated or shared IP issue needs escalation with your ESP
• Corporate filters or recipient-side rules are the main blocker

If your fundamentals are solid and placement is still poor across providers for multiple campaigns, it may be time to involve your ESP’s deliverability team or a specialist.

---

30-minute deliverability triage flow

Use this sequence in order so you do not waste time chasing the wrong cause.

Step 1: Confirm whether the problem affects all campaigns or only one segment

Start with scope.

Ask:

• Is every campaign underperforming?
• Is the issue limited to one audience segment?
• Did it start after a giveaway, webinar, lead magnet, or CRM import?
• Are only newsletters affected while receipts or password resets still inbox?

What the patterns usually suggest:

• All campaigns affected across providers
  Likely authentication, DNS, domain reputation, or a major sending change.

• Only one segment affected
  Usually list quality, acquisition source, relevance, or consent quality.

• Only one campaign affected
  Often content, links, formatting, or subject-line issues.

• Only newsletters affected
  Usually marketing-stream reputation, engagement, cadence, or list quality.

Example:
A SaaS company imports 8,000 trade-show contacts and sends the same newsletter to everyone. Legacy subscribers perform normally. The imported segment tanks. That points to list source and expectation mismatch, not necessarily broken authentication.

Step 2: Check authentication status: SPF, DKIM, and DMARC

Authentication is baseline in 2026. It is not optional.

At minimum, verify:

• SPF exists and includes your actual sending service
• DKIM signing is active for the domain or subdomain you use
• DMARC exists and matches your From-domain strategy
• At least SPF or DKIM passes and aligns with the visible From domain

Good places to check:

• Your ESP’s authentication dashboard
• DNS lookup tools such as MXToolbox
• Google Postmaster Tools if you have enough Google volume
• Your DNS provider panel

If you recently changed ESPs, domains, subdomains, or IT settings, stale records are a common cause.

Step 3: Review bounce, complaint, and unsubscribe trends

Look at trends across several sends, not just one campaign.

Check:

• Hard bounces
• Soft bounces
• Spam complaints
• Unsubscribes
• Click trends
• Provider-level open trends, with caution

Important nuance: open rates are less reliable than they used to be because of Apple Mail Privacy Protection and image prefetching. Treat opens as a directional signal, not absolute truth.

What these trends often mean:

• Hard bounce spike: invalid or stale addresses, poor list quality
• Soft bounce spike: temporary mailbox issues, throttling, or filtering patterns
• Complaint spike: expectation mismatch, weak acquisition, deceptive messaging, or over-mailing
• Unsubscribe spike: relevance or cadence problem, often before complaints get worse

Step 4: Inspect list source and recent list-growth changes

This catches more problems than most teams expect.

Audit recent additions such as:

• Purchased lists
• Scraped contacts
• Event imports without clear permission
• Co-registration leads
• Giveaway entrants
• Old CRM records reactivated after a long silence
• Lead magnets that attracted the wrong audience

Ask one blunt question:

Did these people clearly expect this exact type of email from this exact sender?

If the answer is fuzzy, deliverability risk goes up.

Step 5: Compare engagement by mailbox provider

Break down results by provider if your ESP supports it:

• Gmail
• Yahoo
• Outlook / Hotmail / Live / Microsoft domains
• Apple-hosted domains if meaningful for your list
• Corporate domains if volume is high enough

This matters because providers weigh signals differently.

Typical patterns:

• Gmail drop only: often engagement or domain reputation
• Microsoft drop only: often filtering, throttling, or local reputation issues
• All major providers drop: broader authentication, list quality, content, or reputation issue

Useful tools:

• Google Email Sender Guidelines
• Google Postmaster Tools
• Microsoft SNDS
• Microsoft JMRP

Availability and depth vary by provider and volume.

Step 6: Review recent content or sending-pattern changes

Ask what changed in the last few sends:

• Bigger send volume than normal?
• Longer gap than usual, followed by a big blast?
• New subject-line style?
• More aggressive offers?
• New template?
• More images and less text?
• New tracking domain?
• Different links or redirect chain?
• New From name or address?

Mailbox providers evaluate trust patterns, not just technical validity. Sudden changes can make legitimate mail look riskier.

Step 7: Check sender reputation signals

You cannot see every reputation model directly, but you can infer a lot.

Reputation is likely part of the issue when:

• Authentication checks out
• Complaints or unsubscribes recently rose
• You mailed a weak or old segment
• Inbox placement gets worse after larger sends
• Engaged users perform much better than the full list
• Gmail is especially weak
• Transactional mail still performs fine, but newsletters do not

Think of sender reputation as accumulated trust. It is built by:

• Good list quality
• Consistent sending
• Low complaints
• Positive engagement
• Stable authentication
• Recognizable branding
• Trustworthy links

And it is damaged by:

• Sudden volume spikes
• Purchased or stale lists
• Repeated sends to inactive contacts
• Misleading subject lines
• Suspicious landing-page links

---

The 30-minute checklist

Use this as a run sheet before your next campaign.

Authentication: Verify SPF is present and aligned

Check now:

• You have one SPF record, not multiple
• It includes your active ESP or sending service
• It does not exceed SPF’s 10-DNS-lookup limit
• The authenticated domain supports your From-domain strategy

Common issues:

• Duplicate SPF records
• Old ESP include statements still in DNS
• New ESP not added
• Sending from one subdomain while authenticating another
• Forwarding edge cases where SPF fails

Plain-English version: SPF is a guest list of servers allowed to send mail for your domain.

Authentication: Verify DKIM signing is active

Check now:

• DKIM is enabled in your ESP
• The selector matches the DNS record your ESP expects
• The key is published and valid
• The signing domain fits your branded sending setup

Common issues:

• DKIM never turned on after setup
• Selector mismatch
• Missing CNAME targets for ESP-managed DKIM
• DNS changes broke signing
• The ESP signs with a different domain than the one you think you are using

Plain-English version: DKIM adds a signature that proves an authorized sender signed the message and it was not altered in transit.

Authentication: Add or review a DMARC policy

Check now:

• A DMARC record exists
• It is published on the correct domain
• It includes a reporting address if you monitor reports
• Your alignment approach matches your visible From domain

A basic example looks like this:

v=DMARC1; p=none; rua=mailto:[email protected]

This is only an example. Verify syntax and policy choices before publishing changes.

Important caution:
Do not jump to p=reject unless you understand every legitimate system that sends mail for your domain. A safer first step is visibility and alignment review.

Domain setup: Use a branded sending domain where possible

A branded domain or subdomain gives you more control and often more trust than a generic shared provider domain.

Examples:

• [email protected]
• [email protected]
• [email protected]
• [email protected]

Or use a marketing subdomain such as:

• mail.example.com
• news.example.com

This will not fix reputation by itself, but it supports consistency and control.

If your ESP supports it, separate marketing and transactional streams by subdomain so newsletter issues do not affect password resets or receipts.

From identity: Keep the From name and address consistent

Subscribers are more likely to trust and engage with mail they recognize.

Check now:

• Has your From name changed recently?
• Did you switch from a person name to a generic brand name?
• Did the address move from [email protected] to something unfamiliar?
• Is the reply-to address sensible and monitored?

Bad pattern:

• One week: Sarah from Acme
• Next week: Acme Growth Team
• Next week: Offers Department

That kind of inconsistency can increase deletes, complaints, and distrust.

List hygiene: Remove invalid, bounced, and inactive contacts

Fastest immediate actions:

• Suppress hard bounces right away
• Review repeated soft bounces
• Exclude long-term inactive users from the next broadcast
• Honor unsubscribes and complaint suppressions immediately

This is one of the fastest ways to improve inbox placement without touching infrastructure.

List quality: Stop mailing old or purchased lists

If your list includes any of these, stop using them:

• Purchased lists
• Scraped contacts
• Old CRM exports with no recent engagement
• Event lists without clear mailing consent
• Third-party “targeted” leads

Why these hurt even when they look relevant:

• People do not recognize you
• Addresses may be invalid
• Complaint risk rises
• Engagement is weak
• Spam-trap risk increases
• Providers see poor recipient response

Acquisition: Audit forms, lead magnets, and consent language

The real question is not just “did they submit a form?”

It is:

• Did they understand what they were joining?
• Was newsletter consent explicit?
• Was frequency clear?
• Did the lead magnet attract the right audience?
• Did your welcome email match expectations?

Example:
A coupon form promising “instant discount updates” may attract bargain seekers who later ignore educational newsletters. That mismatch lowers engagement and can drag down reputation.

Engagement: Segment unengaged subscribers before your next send

If deliverability is shaky, do not send your next campaign to everyone.

Instead:

• Create a segment of recent openers, clickers, or converters
• Send to that engaged group first
• Hold back long-term inactive contacts
• Use a re-engagement campaign later for stale segments

This often stabilizes performance faster than any design tweak.

Cadence: Check for sudden spikes in volume or erratic sending

Mailbox providers like consistency.

Risky patterns:

• Sending once a month, then blasting the full database
• Importing a big list and mailing it immediately
• Doubling or tripling normal volume overnight
• Going quiet for a long period, then sending a promotion-heavy burst

A safer pattern is gradual, predictable sending to engaged people first.

Content: Review subject lines for misleading or aggressive language

A single “spam word” is not usually the problem. Trust is.

Review for:

• Fake reply prefixes like Re: or Fwd: when it is not true
• Artificial urgency
• Clickbait that does not match the email
• Excessive all caps
• Misleading claims
• Unexpected offer framing

Bad examples:

• RE: your account update for a newsletter
• FINAL WARNING
• You won't believe this
• Claim this now before it disappears forever

These patterns often increase complaints or silent ignoring.

Content: Reduce spammy formatting and risky link patterns

Check for:

• Too many links
• Mismatched display text and destination URL
• URL shorteners
• Affiliate redirects
• Image-only layouts
• Broken HTML
• Hidden text
• Huge attachments

Plain text matters too. A sensible plain-text version is still a best practice for compatibility and trust.

Links: Check domain reputation of URLs and redirect chains

Providers evaluate not just who sent the email, but also where the email sends people.

Review:

• Every tracked link resolves correctly
• Links use HTTPS
• Landing-page domains match your brand
• Redirects are limited and expected
• Custom link branding is enabled if your ESP supports it

Bad example:

• From address says example.com
• Email links point to bit.ly/...
• Redirect lands on promo-offer-now.net

That is a trust problem.

Reputation: Review complaint rates and spam-trap risk indicators

You usually cannot see spam traps directly, but you can spot risk.

Watch for:

• Complaints rising after a recent list import
• Large sends to old inactive contacts
• Big gaps followed by full-list blasts
• Poor performance from giveaway or co-registration leads
• High delete-without-click behavior where visible
• Good performance from engaged segments but poor performance from full-list sends

Exact complaint thresholds vary by provider and ESP, so focus on trends and investigate spikes quickly.

Infrastructure: Confirm your ESP setup still matches current DNS records

This catches a surprising number of issues.

Review:

• SPF records still include your current ESP
• DKIM selectors still match
• DMARC still exists and is valid
• Branded tracking domains still resolve
• Domain or IT changes did not overwrite records
• Security, CDN, or DNS migrations did not break mail-related settings

This is especially important after:

• Changing ESPs
• Rebranding domains
• Moving DNS providers
• Updating website infrastructure
• Adding new sending tools

---

How to check SPF, DKIM, and DMARC without getting lost in DNS

If DNS feels intimidating, here is the simple version.

DNS is the system that stores your domain settings, including the records that tell mailbox providers which services are allowed to send email on your behalf.

What SPF does in simple terms

SPF says:

“These servers are allowed to send mail for my domain.”

Think of it as a guest list.

A simplified example:

v=spf1 include:_spf.google.com include:sendgrid.net ~all

That is only illustrative. Your actual record depends on your sending tools.

What to look for:

• Only one SPF record
• Your active sender is included
• Old services are removed
• No SPF lookup-limit issues

One subtle point: SPF can break during forwarding because the forwarder sends from a different server. That is one reason DKIM matters so much.

What DKIM does in simple terms

DKIM says:

“This message was signed by an authorized sender, and the content was not altered in transit.”

It uses a cryptographic signature.

You will usually see DKIM configured through records tied to a selector, such as:

• s1._domainkey.example.com
• k1._domainkey.mail.example.com

What to look for:

• DKIM is enabled in your ESP
• The published selector matches what your ESP expects
• The sending domain or subdomain is the one you intended

DKIM often survives forwarding better than SPF, as long as the message is not modified too heavily.

What DMARC does in simple terms

DMARC says:

“Here is how to evaluate my authenticated mail, and here is where to send reports.”

It builds on SPF and DKIM.

A simple starter record can look like:

v=DMARC1; p=none; rua=mailto:[email protected]

Again, verify syntax before use.

What DMARC helps you do:

• Define policy for failed authentication
• Get reporting visibility
• Support trust and alignment
• Reduce spoofing risk

What alignment means and why it matters

Alignment is where many senders get tripped up.

A message can technically pass SPF or DKIM, but still fail DMARC alignment if the authenticated domain does not match the visible From domain closely enough.

Simple example:

• Visible From address: [email protected]
• DKIM signs as mailer.otherdomain.com
• SPF passes on bounce.espdomain.com

In that setup, mail may pass raw authentication checks, but DMARC alignment may still fail because the authenticated identity does not align with example.com.

Practical rule:

• For DMARC to pass, either SPF or DKIM must pass and align
• In practice, configure both

Common setup mistakes that cause spam-folder placement

Watch for these:

• Duplicate SPF records
• SPF over the 10-lookup limit
• DKIM selector mismatch
• Missing CNAME records for ESP-managed DKIM
• DMARC syntax errors
• Sending from one subdomain while authenticating another
• Changing ESPs but leaving stale DNS
• IT overwriting records during a DNS migration
• Publishing DMARC without checking whether real senders align

Useful references:

• DMARC.org
• RFC 7208 for SPF
• RFC 6376 for DKIM
• RFC 7489 for DMARC

---

List hygiene fixes that improve deliverability fastest

If you need the fastest non-technical wins, start here.

Suppress hard bounces immediately

A hard bounce means the address is invalid or permanently unavailable.

Do this now:

• Suppress hard bounces permanently
• Do not retry them in future campaigns
• Review where those addresses came from

If hard bounces rise after a new import, the list source is likely poor.

Watch soft bounces for pattern changes

A soft bounce is temporary, but patterns matter.

Examples:

• Mailbox full
• Temporary server issue
• Rate limiting
• Throttling
• Short-term block

One soft bounce is not a crisis. A sharp increase across one provider can signal filtering or reputation issues.

Identify and isolate inactive subscribers

Not every inactive user is harmful, but mailing a large inactive segment during a deliverability problem is risky.

A practical approach:

• Build a segment of recent clickers and openers
• Separate users inactive for a long period
• Pause broad sends to the inactive group
• Test re-engagement separately

The exact inactivity window depends on send frequency. A daily newsletter and a monthly newsletter should not use the same recency rule.

Why purchased or scraped lists hurt even if they are “targeted”

“Targeted” is not the same as permission-based.

Purchased and scraped lists hurt because:

• Recipients did not ask for your email
• Recognition is low
• Complaints rise
• Addresses are often stale
• Some may be traps or abandoned accounts
• Positive engagement is weak

Even if a few conversions happen, the reputation damage usually costs more.

When to use re-engagement instead of sending to everyone

A re-engagement sequence is safer when:

• The segment is old
• Contacts have not clicked or opened in a long time
• You changed newsletter positioning
• You imported legacy records from a CRM

A simple approach:

1. Send a clear “still want these emails?” message
2. Offer a reason to stay subscribed
3. Make unsubscribe easy
4. Suppress people who do not engage

That is much safer than dragging inactive users through regular campaigns forever.

---

Content and formatting issues that can trigger filtering

Content alone rarely explains everything, but it often contributes.

Subject lines that create trust issues

Providers care about user response. Users care about whether your message feels honest.

Risky patterns:

• Fake urgency
• Misleading personalization
• Bait-and-switch offers
• Fake account alerts
• Reply-style deception

Better approach:

• Match the actual content
• Be specific
• Be recognizable
• Set the right expectation

Too many links, mismatched URLs, and URL shorteners

Link trust matters.

Review for:

• Excessive links in a short email
• Displayed URL not matching the actual destination
• Shorteners like bit.ly
• Redirect chains through multiple domains
• Affiliate or tracking hops that look unrelated to your brand

If the email says your brand but the click path says something else, filters and users both get suspicious.

Image-heavy emails with little supporting text

Image-heavy emails can reduce clarity and trust.

Problems include:

• Less context for filters and readers
• Weak accessibility
• Poor fallback if images are blocked
• Low information density

A practical rule: use images to support the message, not replace it.

Overuse of promotional wording, urgency, or deceptive claims

There is no magical universal “bad word” list. But hype-heavy patterns can still hurt.

Review for:

• Repeated scarcity language
• Overblown claims
• Too-good-to-be-true framing
• Unclear offer terms
• Promotional tone that clashes with subscriber expectations

Often the bigger issue is not filtering logic alone. It is that these emails generate more complaints, deletes, and non-engagement.

HTML problems, attachment risks, and plain-text alternatives

Check the technical presentation too.

Watch for:

• Broken HTML
• Hidden or tiny text
• Poor mobile rendering
• Heavy attachments
• Missing plain-text version

Attachments can be especially risky in newsletters. When possible, link to hosted assets instead of attaching files.

---

Sender reputation: the hidden factor behind spam-folder problems

Authentication gets you recognized. Reputation determines whether you are trusted.

How mailbox providers use engagement and complaint signals

Providers do not publish exact formulas, but they clearly use behavioral signals such as:

• Opens
• Clicks
• Replies
• Moving mail out of spam
• Adding a sender to contacts
• Complaints
• Deletes without reading

That is why a technically valid campaign can still land in spam if recipients consistently ignore it.

Why sudden volume changes can hurt even legitimate senders

Legitimate businesses run into this all the time.

Examples:

• A creator sends one small newsletter per month, then blasts a large sales email to the full historical list
• An ecommerce store imports old subscribers before Black Friday
• A SaaS team revives dormant leads and emails them all at once

To providers, that can look unstable or risky.

The role of sending domain and IP reputation

For most beginners, domain reputation matters more day to day than IP theory.

Still, both can matter:

• Domain reputation: trust associated with your sending domain
• IP reputation: trust associated with the sending IP

If you use a shared IP through an ESP, much of the infrastructure is managed for you. But poor list quality and weak engagement can still hurt your domain reputation. So blaming the shared IP first is often the wrong move.

How to spot whether reputation is likely your real issue

Reputation is a strong suspect when:

• SPF, DKIM, and DMARC are correct
• Spam-folder placement happens across multiple campaigns
• Full-list sends perform worse than engaged segments
• Gmail is significantly weaker than before
• Complaints or unsubscribes rose before placement worsened
• A list-growth campaign brought in weak subscribers
• Transactional mail still performs well

Reputation recovery is rarely instant. Once the root cause is fixed, improvement can take days or weeks depending on volume, provider, and the level of damage.

---

Quick fixes by symptom

Use this table when you need to prioritize fast.

Symptom	Likely causes	First fixes
All emails go to spam across providers	Broken auth, DNS mismatch, poor domain reputation, bad list import, risky links	Verify SPF/DKIM/DMARC, check DNS, suppress risky segments, review links and recent volume changes
Only Gmail placement dropped	Weak engagement, Gmail domain reputation issue, stale segments, irrelevant content	Send to engaged users first, review Gmail trends in Postmaster Tools, pause old segments
Outlook or Microsoft filters more aggressively	Microsoft-side reputation, throttling, sudden volume changes, list-quality issues	Review SNDS/JMRP options, reduce volume spikes, tighten segmentation, review bounces
Transactional emails inbox but newsletters do not	Marketing-stream content, cadence, segment quality, newsletter reputation	Separate streams if possible, prune the list, review content and links, send to engaged users only
New domain or subdomain underperforms	No established reputation, weak warmup, too much volume too soon	Warm up gradually, start with highly engaged users, keep volume steady
One segment performs badly while others are fine	Poor acquisition source, weak consent, old imported list	Pause that segment, audit the source, run re-engagement or suppress
Bounce and unsubscribe rates suddenly rise	Bad list source, stale records, expectation mismatch	Suppress hard bounces, review consent source, adjust frequency and segmentation

If all emails go to spam across providers

Check first:

• SPF, DKIM, DMARC
• DNS changes
• From-domain alignment
• New tracking or landing-page domains
• Broad list-quality issues
• Recent volume spikes

This pattern usually points to something bigger than one subject line.

If only Gmail placement dropped

Focus on:

• Engagement quality
• Old or low-intent segments
• Gmail-specific reputation clues
• Recent volume changes
• Content people ignore instead of clicking

Gmail tends to weigh engagement and domain reputation heavily.

If Microsoft or Outlook filters you more aggressively

Outlook-family properties can be more sensitive to certain filtering and throttling patterns.

Review:

• Soft bounce patterns
• Recent send spikes
• SNDS data if available
• Complaint patterns
• Whether Outlook recipients are less engaged than Gmail recipients

If transactional emails land in inbox but newsletters do not

That is actually a useful clue.

It often means:

• Your domain is not fundamentally broken
• The issue is tied to the marketing stream
• Content, cadence, list quality, or newsletter reputation is the better place to look first

If possible, isolate marketing and transactional streams on separate subdomains.

If a new domain or subdomain is underperforming

New sending domains usually need trust built gradually.

Safer approach:

• Start with your most engaged subscribers
• Keep volume consistent
• Avoid blasting old segments
• Maintain authentication from day one

A new subdomain is not a fresh start if you keep the same weak list habits.

---

What not to do when trying to fix deliverability

Some “tests” make things worse.

Do not blast your full list to test inbox placement

A full-list blast to a weak audience often creates:

• More complaints
• More ignoring
• Worse reputation
• Less clarity about the root cause

Test with engaged segments first.

Do not switch platforms before checking fundamentals

If your real issue is:

• Broken authentication
• Poor list quality
• Bad acquisition
• Weak engagement
• Suspicious links
• Erratic sending

...that problem usually follows you to the new ESP.

Do not keep resending to unengaged contacts

Repeatedly emailing people who do not respond tells providers your messages are less wanted than you think.

If someone has been cold for a long time, use re-engagement or suppression.

Do not “fix” low opens with misleading subject lines

Short-term curiosity tactics often create long-term trust damage.

If a subscriber feels tricked, the next click may be the spam button.

---

A simple weekly maintenance routine

You do not need a giant compliance process. You need a repeatable one.

5-minute checks before each campaign

Before every send, review:

• Authentication still valid in your ESP
• No DNS changes broke SPF, DKIM, or branded links
• Suppression lists are current
• You are not mailing hard bounces or obvious dead segments
• Unsubscribe works cleanly
• Volume is in line with recent sends
• Links are on-brand, secure, and functional
• From name and address are recognizable

For bulk senders, visible and functional unsubscribe handling is especially important under major provider expectations.

Weekly metrics to watch

Track trends, not isolated numbers:

• Hard bounces
• Soft bounces
• Complaints
• Unsubscribes
• Click rates
• Conversion rates
• Provider-level engagement trends
• Inbox placement clues from test inboxes or provider tools

Open rates can still be directionally useful, but do not treat them as the single source of truth.

Monthly DNS and domain-health review

Once a month, check:

• SPF includes current senders only
• DKIM selectors still resolve
• DMARC still exists and is valid
• Sending and tracking domains are branded properly
• New tools are not sending without authentication
• IT or website changes did not alter mail records

This is also a good time to review whether your acquisition sources still match subscriber expectations.

When to escalate to your ESP or a deliverability specialist

Escalate when:

• Authentication is correct
• List hygiene is under control
• Complaints are low
• You still see broad spam placement across major providers
• The issue persists across multiple campaigns
• Provider-specific reputation signals show deterioration you cannot explain
• You have a complex setup with multiple sending systems

Bring useful evidence when you escalate:

• DNS screenshots or lookup results
• Provider-level trends
• Bounce and complaint history
• Recent sending changes
• Segment comparisons
• Example message headers if requested

That makes support faster and more useful.

---

FAQ

What is the difference between email delivery and deliverability?

Delivery means the receiving server accepted your message. Deliverability is your ability to reach the inbox consistently over time. A message can be delivered but still land in spam, promotions, or another filtered location.

Why are my newsletters going to spam all of a sudden?

Sudden spam placement usually points to one or more changes: broken or misaligned SPF, DKIM, or DMARC records, a recent list import, lower engagement, higher complaints, a sending-volume spike, or content and link changes that reduce trust.

Can SPF, DKIM, and DMARC fix spam-folder problems immediately?

They can fix authentication issues quickly if setup is missing or broken, but they do not guarantee inbox placement on their own. If sender reputation or list quality is the real issue, recovery can take longer even after authentication is corrected.

Do I need both SPF and DKIM for DMARC to work?

For DMARC to pass, either SPF or DKIM must pass and align with the visible From domain. In practice, you should configure both because they improve deliverability, troubleshooting, and resilience across different mail flows.

What should I check first before switching email platforms?

Check the basics first: authentication, DNS alignment, bounce and complaint trends, recent list-growth sources, mailbox-provider differences, and any recent content or cadence changes. If those issues follow you, changing ESPs will not solve the root problem.

How can I tell if the issue is list quality or sender reputation?

If engaged segments perform better than old or newly imported segments, list quality is a strong suspect. If authentication is correct but inbox placement drops across major providers, complaints rise, or only large sends perform badly, sender reputation is more likely involved.

Why do transactional emails reach the inbox while newsletters go to spam?

That usually means your domain is not completely broken. Marketing messages often face stricter engagement and reputation scrutiny than transactional mail, so the issue is usually tied to newsletter content, cadence, audience quality, or the reputation of the marketing stream.

How often should I clean my email list?

Review list hygiene before every campaign at a basic level and do a deeper cleanup regularly. Suppress hard bounces immediately, monitor soft bounces for patterns, and segment or re-engage inactive subscribers instead of emailing everyone indefinitely.

---

Final checklist summary

If you want the shortest version, use this order:

1. Check scope: all campaigns, one segment, or one provider?
2. Verify authentication: SPF, DKIM, DMARC, and alignment
3. Review trends: hard bounces, soft bounces, complaints, unsubscribes
4. Audit list sources: imports, giveaways, old CRM records, purchased leads
5. Compare providers: Gmail, Yahoo, Outlook
6. Review changes: volume, cadence, subject lines, links, templates
7. Protect reputation: send to engaged users first, suppress risky segments
8. Confirm infrastructure: current ESP setup still matches DNS

If your newsletters are landing in spam, run this checklist before blaming your copy or replacing your ESP. In most cases, the fastest gains come from fixing trust signals and tightening who you send to. Then monitor weekly so a small deliverability wobble does not turn into a reputation problem.

email deliverability checklist, fix emails going to spam, email spam folder problems, SPF DKIM DMARC checklist, improve email deliverability, newsletter deliverability, sender reputation, inbox placement, email authentication, list hygiene