Why Your Emails Go to Spam (And How to Fix It)

Quick diagnosis

Check your authentication first—it's the most common cause of spam issues.

1. Missing or Broken Email Authentication

This is the #1 reason emails go to spam. Without proper authentication, receiving servers can't verify that you're actually authorized to send email from your domain.

What to Check

Common Problems

No SPF record

Problem: Receiving servers don't know which IPs can send for you Fix: Add a TXT record like: v=spf1 include:_spf.google.com ~all

Multiple SPF records

Problem: Having more than one SPF record breaks SPF entirely Fix: Combine all includes into a single record

No DMARC record

Problem: Servers don't know what to do with suspicious emails Fix: Add: v=DMARC1; p=none; rua=mailto:dmarc@yourdomain.com

SPF uses +all

Problem: This allows ANYONE to send email as your domain Fix: Change +all to ~all (soft fail) or -all (hard fail)

How to Fix

1. Run your domain through the Email Deliverability Checker.
2. Fix any issues identified using the detailed guides:
   • Fix SPF Records
   • Fix DMARC Records
   • Set Up DKIM
3. Wait 24-48 hours for DNS changes to propagate
4. Test again

2. Poor Sender Reputation

Even with perfect authentication, your emails can hit spam if your sending reputation is poor. Reputation is like a credit score for email senders.

What Hurts Your Reputation

• High bounce rates — Sending to invalid addresses
• Spam complaints — Recipients marking you as spam
• Spam traps — Sending to addresses designed to catch spammers
• Inconsistent volume — Sudden spikes in sending
• Low engagement — Recipients ignoring your emails

How to Check Your Reputation

• Google Postmaster Tools — See how Gmail views your domain
• Microsoft SNDS — Check reputation with Microsoft
• Sender Score — Free reputation check

How to Fix

1. Clean your list — Remove bouncing addresses immediately
2. Add unsubscribe links — Make it easy to opt out (required by law)
3. Warm up gradually — Don't suddenly send 10x more email
4. Monitor complaints — Use feedback loops to remove complainers
5. Re-engage or remove — Inactive subscribers hurt your metrics

3. Spammy Email Content

Spam filters analyze your email content for patterns that look like spam. Even legitimate emails can trigger these filters.

Red Flags in Subject Lines

• ALL CAPS: "FREE MONEY NOW!!!"
• Excessive punctuation: "Act now!!!"
• Spam trigger words: "Congratulations", "Winner", "Free gift"
• Misleading text: "RE:" or "FWD:" on new emails

Red Flags in Email Body

• Too many links (especially to suspicious domains)
• Large images with little text
• URL shorteners (like bit.ly)
• Attachments (especially .exe, .zip)
• Hidden text or tiny fonts
• Too much red or green text

Better Practices

❌ Bad: "CONGRATULATIONS!!! You've WON a FREE iPhone!!! Click HERE NOW!!!"

✓ Good: "Your order is confirmed - here's what happens next"

4. Technical Issues

Sometimes the problem is more technical.

Missing MX Records

If your domain can't receive email, some spam filters flag this as suspicious.

Check: Does your domain have MX records?

Fix: How to Configure MX Records

Blacklisted IP Address

Your sending IP might be on a blocklist due to previous abuse (even from other users on shared servers).

Check: MXToolbox Blacklist Check

Fix: Request delisting or use a different sending service

Reverse DNS Not Configured

Many spam filters check if your sending IP has valid reverse DNS.

Check: Does your IP resolve to a hostname that resolves back to the IP?

Fix: Contact your email service provider or hosting company

5. Engagement Signals

Modern spam filters track how recipients interact with your emails.

Positive Signals

• Opening emails
• Clicking links
• Replying
• Moving from spam to inbox
• Adding to contacts

Negative Signals

• Deleting without opening
• Marking as spam
• Never opening

How to Improve

1. Only email engaged subscribers — Segment out inactive users
2. Send relevant content — Match content to subscriber interests
3. Optimize send times — Test when your audience is most active
4. Make emails scannable — Clear headers, short paragraphs
5. Include a clear call-to-action — Give people a reason to engage

Quick Wins Checklist

Start with these high-impact fixes:

• ☐Set up SPF — Takes 5 minutes, huge impact
• ☐Set up DKIM — Your email provider handles the hard part
• ☐Add DMARC — Even p=none helps
• ☐Add unsubscribe link — Required by law, reduces complaints
• ☐Clean your list — Remove bounces and inactive subscribers
• ☐Check blacklists — Free and takes 2 minutes

Summary

Most spam folder issues come down to three things:

1. Authentication — SPF, DKIM, and DMARC must be configured
2. Reputation — Keep your list clean and engagement high
3. Content — Avoid spammy words and formatting

Start by checking your authentication with the Email Deliverability Checker. It's the fastest way to identify and fix the most common problems.