First, Confirm the Problem
Before changing anything, check what's actually happening:
- Is it every inbox or just one provider? Look at opens and clicks by domain, such as Gmail vs Outlook.
- Did it start suddenly? A sudden change usually has a specific cause, such as a new list or a DNS change.
- Is it all emails or certain ones? One campaign landing in spam points to content or a specific segment.
Send a test to addresses at several providers and check where it lands.
Ten Common Causes
| Cause | Fix |
|---|---|
| Set up custom DKIM and a DMARC record |
| Use an address on your own domain |
| Stop emailing it; send only to opted-in subscribers |
| Re-engage, then remove those who don't respond |
| Remind people why they joined; make unsubscribing easy |
| Increase sending gradually |
| Remove invalid addresses; consider confirmed opt-in |
| Match subject lines to content honestly |
| Use trusted links and well-built templates |
| Keep your From name and address stable |
Causes 1 and 2: Authentication
Without authentication, inboxes can't confirm your emails are legitimate. Gmail, Yahoo and Outlook now require it for high-volume senders, and it helps everyone.
Free addresses like Gmail can't be authenticated by your email platform, so always send from your own domain. See SPF, DKIM and DMARC setup.
Causes 3 and 4: List Quality
Old lists contain abandoned addresses, some of which may have been turned into spam traps. Purchased lists contain people who never agreed to hear from you.
Inactive subscribers also hurt, because inboxes notice when many recipients ignore your emails. See email list hygiene and re-engagement email campaign.
Cause 5: Spam Complaints
When people mark your email as spam, it carries significant weight. Gmail and Yahoo expect complaint rates well below 0.3%. See Gmail and Yahoo sender requirements.
People often report spam because they don't recognize the sender, receive more email than expected or can't find the unsubscribe link. Fix all three.
Causes 6 and 7: Volume and Bounces
Sending far more than usual all at once, such as emailing a large list after months of silence, looks suspicious. Increase volume gradually, starting with your most engaged subscribers.
High bounce rates signal a poorly maintained list. See email bounce rate.
Causes 8 to 10: Content and Consistency
Content matters less than reputation, but misleading subject lines, link shorteners, broken HTML or emails made of a single image can tip the balance. Changing your sender name and address often also confuses inboxes and readers.
See spam trigger words and email design best practices.
A Recovery Plan
- Check authentication and fix any failures.
- Pause sends to inactive and unverified subscribers.
- Send to your most engaged segment for a few weeks, such as people who clicked recently.
- Gradually add back less engaged subscribers.
- Monitor complaints and bounces after each send.
- Check whether you're on a blocklist. See email blacklist.
Recovery takes time. Consistent, wanted emails are what rebuild reputation.
Authenticate your domain, segment by engagement and send to a clean list with AWeber.
Spam Folder FAQs
Why are my emails going to spam?
Common causes are missing authentication, poor list quality, spam complaints and sudden volume spikes.
How do I stop my emails going to spam?
Authenticate your domain, send only to opted-in subscribers, clean your list and keep complaints low.
Do certain words send emails to spam?
Rarely on their own. Reputation and engagement matter much more.
How long does it take to fix spam folder problems?
It varies. Consistent sending to engaged subscribers usually improves things over several weeks.