### 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

| Record | What It Does | How to Check |
| --- | --- | --- |
| SPF | Lists authorized sending servers | TXT record at your domain |
| DKIM | Adds cryptographic signature | TXT record at selector._domainkey.yourdomain.com |
| DMARC | Sets policy for failed checks | TXT record at _dmarc.yourdomain.com |

### 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.