Why Are My Emails Going to Spam? (6 Real Causes + Fixes)
April 18, 2026 • InboxGreenEmail Team
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Your email left your server. Gmail received it. But instead of the inbox, it went to spam. No bounce, no error — just silence.
This is the most common deliverability complaint in 2025, and it almost always comes down to one of six root causes.
Here's a plain-English breakdown of why emails go to spam — and what to do about each one.
1. Missing or broken SPF, DKIM, or DMARC
This is the first thing every mail filter checks. If your domain doesn't have these three DNS records set up correctly, Gmail and Outlook treat your email as suspicious by default.
- SPF tells receiving servers which IPs are allowed to send for your domain.
- DKIM proves the email wasn't tampered with in transit (a cryptographic signature).
- DMARC ties SPF and DKIM together and tells servers what to do with failures.
If any of these are missing, wrong, or misaligned, your emails go to spam — even if you're not spamming anyone.
Fix it: Run a free check at InboxGreen.email/check. It shows exactly what's missing and what to fix.
2. Your domain or IP is on a blacklist
Blacklists are lists of domains and IPs known to send spam or phishing. If you're on one, most mail providers will either block your email outright or send it to spam automatically.
You can end up on a blacklist by:
- Sending to old, unengaged lists
- Having a high spam complaint rate (above 0.1% in Gmail)
- Using a shared sending IP that someone else abused
- Sending too much email too fast from a new domain
Fix it: Check your domain and sending IP against 100+ blacklists with the free Blacklist Checker. If you're listed, most blacklists have a removal form.
3. Too many people are clicking "This is spam"
Gmail tracks how often recipients mark your emails as spam. If your spam complaint rate goes above 0.1%, Google starts filtering more of your mail. Above 0.3% and you'll see massive inbox drops.
This usually happens when:
- Your unsubscribe link is broken, hard to find, or requires logging in
- You're emailing people who never explicitly opted in
- Your send frequency suddenly increases
- Your content looks like an ad when subscribers expected a personal email
Fix it: Add one-click List-Unsubscribe headers to your emails. This is now required by Gmail and Yahoo for bulk senders.
4. Your domain is new (less than 30–60 days old)
New domains have no sending reputation. Mail providers are cautious by default. Even if everything is set up perfectly — SPF, DKIM, DMARC all passing — a brand-new domain will often get filtered until it builds a track record.
The solution is domain and IP warm-up: start sending very small volumes to your most engaged contacts, then slowly increase over 4–8 weeks. Never blast a cold list on day one.
5. Your email content triggers spam filters
Content filters look at what's inside your email. Common triggers:
- Phrases like "you've been selected", "act now", "100% free", "no credit card required" in the subject
- Images with almost no text (spam images are common)
- Links to domains with bad reputation
- All-caps subject lines
- Missing plain-text version
- Mismatched or spoofed "From" display names
The easiest test: send a copy to a test Gmail address and check the "Show original" view. If Authentication-Results shows any FAIL, fix that first. Then look at the content.
6. Your sending infrastructure isn't set up for bulk mail
If you're sending transactional or marketing emails through Mailchimp, Klaviyo, SendGrid, Mailgun, Amazon SES, or similar — your sending domain still needs its own SPF and DKIM records pointing to that provider.
A lot of businesses miss this: they sign up for an ESP (email service provider) but never update their DNS. The ESP sends mail "from" your domain, but without authentication, it fails alignment and goes straight to spam.
Fix it: Check what records your ESP needs and run your domain through InboxGreen.email/check to see if they're actually live.
The fastest way to diagnose why your email is going to spam
- Go to InboxGreen.email/check and enter your sending domain.
- Look at the SPF, DKIM, and DMARC results. Fix any failures first.
- Check your domain against blacklists with the Blacklist Checker.
- Send a test email to Gmail and open "Show original" — read the Authentication-Results header.
- If everything is passing, look at your content, list quality, and sending frequency.
The good news: most "emails going to spam" problems are fixable in an afternoon. SPF, DKIM, and DMARC fixes are just DNS changes — no code required.
If you want a step-by-step fix plan with copy-paste DNS records, the InboxGreen FixKit generates them for your exact domain in under a minute.
Free Deliverability Scan
Check SPF, DKIM, DMARC and List-Unsubscribe for your domain in seconds.