Why Are My Emails Going to Spam? 12 Fixes That Actually Work
The real reasons marketing emails land in spam — authentication, list quality, content and sending habits — and 12 practical fixes for small businesses.
In short: Spam filters mostly judge who you are (authentication), whether people want your email (engagement and complaints) and only then what the email says. Authenticate your domain, email only people who opted in, remove bounces and inactive subscribers, and make unsubscribing effortless — those four steps fix most spam-folder problems.
Few things are more frustrating than writing a great email and discovering it went straight to spam. The good news: spam filtering isn't random. Mailbox providers like Gmail, Outlook and Yahoo look at a handful of signals — and you control most of them.
How spam filters decide
Filters ask three questions:
- Can we prove this email really comes from this sender? (authentication)
- Do people who get email from this sender want it? (reputation and engagement)
- Does this message look like spam? (content and technical quality)
The first two matter far more than the words you use.
12 fixes, in order of impact
1. Authenticate your domain (SPF, DKIM, DMARC)
Unauthenticated email is increasingly rejected or spam-foldered, especially by Gmail and Yahoo. Publish SPF, DKIM and DMARC records for your sending domain. It sounds technical, but it's a one-time copy-and-paste job — see SPF, DKIM and DMARC explained.
2. Send from your own domain, not Gmail or Yahoo
"you@yourbusiness.com" can be authenticated. "yourbusiness@gmail.com" sent through a marketing platform can't, and Gmail and Yahoo's own policies cause those emails to fail.
3. Only email people who opted in
Bought or scraped lists generate complaints and bounces — the fastest way to the spam folder.
4. Remove addresses that bounce
Hard bounces (addresses that don't exist) must never be emailed again. A good platform does this automatically.
5. Stop emailing people who never engage
If someone hasn't opened or clicked in six months, they're dragging your reputation down. Try a re-engagement campaign, then remove those who still don't respond.
6. Make unsubscribing easy
When unsubscribing is hard, people click "Report spam" instead — and complaints hurt you far more than unsubscribes. Use a one-click unsubscribe link and header.
7. Keep spam complaints extremely low
Gmail asks bulk senders to keep their reported spam rate below 0.3%, and ideally under 0.1%. That's at most one complaint per thousand emails.
8. Send consistently
Big, irregular blasts after months of silence look suspicious. A steady rhythm builds a steady reputation.
9. Warm up a new domain or server slowly
If your domain or sending server is new, start with your most engaged subscribers and increase volume gradually over a few weeks.
10. Write like a human
Avoid ALL CAPS subject lines, rows of exclamation marks and misleading "RE:" or "Your order" subjects. Write clearly about what's inside.
11. Balance images and text
An email that's one big image with no text looks suspicious and is unreadable when images are blocked. Use real text, with images to support it, and add alt text.
12. Watch your links
Link to reputable sites, avoid URL shorteners and make sure every link works.
How to check where you stand
- Send a test to your own Gmail, Outlook and Yahoo addresses and see where it lands.
- In Gmail, open the email, choose Show original, and check that SPF, DKIM and DMARC say PASS.
- Set up Google Postmaster Tools for your domain to see your spam rate and reputation at Gmail.
How to diagnose your problem, step by step
Before changing anything, find out where the problem is. Spam placement is rarely "everyone, everywhere".
Step 1: Test the three big inboxes
Create free test addresses at Gmail, Outlook.com and Yahoo, add them to your list, and send your next campaign. Note where it lands in each. Different results point to different causes:
- Spam everywhere: usually authentication or a damaged domain reputation.
- Spam only at Outlook/Hotmail: Microsoft is often stricter with new senders and new servers — slow down and warm up.
- Promotions tab at Gmail: that's normal for marketing email and not spam.
Step 2: Read the email's "report card"
In Gmail, open your test email, click the three dots and choose Show original. Look at three lines: SPF, DKIM and DMARC. All three should say PASS. If any say FAIL or are missing, fix authentication first — nothing else will help until it passes.
Step 3: Check your list quality
Look at your last few campaigns:
- Bounce rate above 2%? Your list contains old or mistyped addresses. Remove hard bounces (good platforms do it automatically) and stop importing old lists.
- Complaint rate above 0.1%? People don't recognise you or didn't ask for your emails. Check how they joined and make your sender name obvious.
- Opens and clicks falling for months? Inactive subscribers are pulling your reputation down.
Step 4: Look at sending patterns
Did you go from 200 emails a week to 5,000 in one day? Sudden spikes look like spam to filters. Increase volume gradually — roughly doubling at most from one send to the next — and send to your most engaged subscribers first.
A worked example
A small online tea shop noticed its open rate drop by half in a month. Their tests showed spam placement at Gmail. "Show original" revealed DKIM: FAIL — they had changed their website host, and the new host had overwritten their DNS records. They re-added the DKIM record, confirmed all three checks passed, sent the next campaign only to people who had clicked in the last 90 days, and returned to their full list two weeks later. Inbox placement recovered within a couple of campaigns.
The lesson: most "sudden spam problems" have one specific cause. Diagnose before you rewrite your emails.
What doesn't help (much)
- Avoiding "spam words". Modern filters care far more about your reputation than about the word "free".
- Changing your sending address or domain to start fresh. A brand-new domain has no reputation at all, which is its own problem — and it looks like evasion.
- Sending more to make up for lower opens. It makes the reputation problem worse.
How Reepio protects your inbox placement
Reepio walks you through domain authentication with copy-and-paste DNS records, removes bounces and complaints automatically, adds one-click unsubscribe headers, checks every send against your suppression list and pauses campaigns automatically if bounce or complaint rates spike. Start free.
Frequently asked questions
How do I know if my emails are going to spam?
Send tests to your own Gmail, Outlook and Yahoo addresses, watch for sudden drops in opens and clicks, and set up Google Postmaster Tools to see your domain reputation and spam rate at Gmail.
Will removing subscribers really help deliverability?
Yes. Mailbox providers watch how recipients engage. Removing addresses that bounce or haven’t engaged in months raises your engagement rate and protects your reputation for everyone else on your list.
Why do my emails land in the Promotions tab?
Gmail’s Promotions tab is where most marketing email belongs, and it isn’t spam. Subscribers still see it. Focus on getting out of the spam folder, and encourage subscribers to move you to their main inbox if they want to.