Why Are My Emails Going to Spam? (And How to Fix It)
When your email lands in spam it feels random, but it almost never is. Mailbox providers like Gmail and Outlook run your message through a few clear tests, and spam placement usually traces back to one of them. The single most common cause, and the one people overlook, is email authentication. Start there, then work down the list. You can check your authentication in ten seconds before anything else.
1. Your authentication is missing or failing (start here)
If your domain doesn't pass SPF and DKIM, and increasingly if it has no DMARC policy, mailbox providers treat you as untrusted and route you to spam, or reject you outright. This is the highest-leverage fix because it's binary: either your mail is properly authenticated or it isn't.
- SPF lists who can send for your domain. Fix a broken SPF record.
- DKIM signs your mail so it can't be tampered with. Set up DKIM.
- DMARC ties them together and tells receivers what to do with fakes. Set up DMARC.
Get all three passing and aligned, and you remove the most common reason for spam placement. Run the free checker to confirm where you stand.
2. Your domain or IP reputation is poor
Providers track how recipients react to your mail over time. Lots of spam complaints, hitting unknown or invalid addresses, or sudden spikes in volume all drag your reputation down. If you send from Google Workspace or Microsoft 365, their shared infrastructure carries decent default reputation, so reputation problems usually come from how you send, not where you send from.
3. You're sending from a brand-new domain with no warmup
A domain with no sending history has no reputation, and a sudden burst of mail from it looks exactly like a spam campaign. If you've just set up a domain (or a new sending subdomain), ramp volume gradually over a couple of weeks rather than blasting your whole list on day one.
4. The content is tripping filters
Less common than people assume, but real. Things that hurt: misleading subject lines, a single giant image with almost no text, link shorteners, too many links, risky attachments, and sloppy HTML. Write like a human, keep a sensible text-to-link ratio, and avoid the tricks that spammers use.
5. List hygiene and missing unsubscribe (for bulk mail)
If you send newsletters or campaigns, a clean list matters more than almost anything. Remove bounces and people who never open, never buy lists, and always include a working one-click unsubscribe. High complaint rates are one of the fastest ways to land in spam and stay there.
How to diagnose it in the right order
- Check authentication first. Run your domain through the checker. If SPF, DKIM, or DMARC is failing, fix that before touching anything else.
- Send a test to a seed inbox. Mail yourself and view the original to confirm
spf=pass,dkim=pass, anddmarc=pass. - Check your reputation. If you send volume from Google or Microsoft, their postmaster tools show your reputation and spam rate.
- Then review content and list practices. Once the technical foundation is solid, these are what's left.
Nine times out of ten, fixing authentication moves the needle the most, and it's the part you can verify and fix today.
Start with the foundation: see if your email authentication is passing.
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