Spam Diagnostic Checklist
Step 1: Authentication
| Check | How | Pass Criteria |
|---|---|---|
| SPF | Sender Domains > click domain > check SPF status | Shows Success (green) |
| DKIM | Sender Domains > click domain > check DKIM status | Shows Success (green) |
| DMARC | Sender Domains > click domain > check DMARC status | Shows Success (green) |
| DMARC alignment | DMARC policy aligns with SPF and DKIM domains | p=none minimum, p=quarantine or p=reject recommended |
Step 2: Sender Reputation
| Check | How | Red Flag |
|---|---|---|
| Complaint rate | Delivery Events > filter Complained > calculate rate | Above 0.1% (1 per 1,000 emails) |
| Bounce rate | Delivery Events > filter HardBounced > calculate rate | Above 2% |
| Blocklist status | Check MxToolbox.com or similar | Any active listing |
| Google Postmaster Tools | Set up at postmaster.google.com | Domain reputation "Low" or "Bad" |
Step 3: Email Content
| Check | Fix |
|---|---|
| No unsubscribe link | Add {EEUnsubscribeLink} to email body |
| No plain text version | Add plain text version in Email Content editor |
| High image-to-text ratio | Add more text content, reduce images |
| Spam trigger words | Remove "free", "act now", "limited time", "winner", "congratulations" |
| ALL CAPS in subject/body | Use normal capitalization |
| Excessive exclamation marks | Limit to one per sentence maximum |
| Shortened URLs | Use full destination URLs |
| No physical address | Include company address (required by CAN-SPAM) |
Step 4: List Hygiene
| Check | Fix |
|---|---|
| Stale list (no engagement in 90+ days) | Create a Segment for engaged contacts only |
| High hard bounce rate | Suppress hard-bounced addresses via Suppression Lists |
| Purchased or scraped list | Never send to purchased lists — they contain spam traps |
| No double opt-in | Implement confirmation for new signups via Pages & Forms |
Step 5: Sending Practices
| Check | Fix |
|---|---|
| New domain, high volume | Use Warm-up schedule in Schedule to gradually increase |
| No Volume Caps | Set Volume Caps on Send Integration to control hourly/daily rate |
| Inconsistent sending | Send on a regular schedule — erratic patterns look suspicious |
| Sending to inactive contacts | Segment by last engagement date, exclude 90+ day inactive |
Common Spam Filter Triggers by Provider
Gmail
- Checks engagement (opens/clicks) heavily — low engagement = more spam
- Google Postmaster Tools shows domain/IP reputation
- DMARC alignment is strictly enforced
Microsoft (Outlook/Hotmail)
- Smart Network Data Services (SNDS) shows IP reputation
- Strict on content — avoid "salesy" language
- Check junkmail@office365.microsoft.com for false positive reports
Yahoo/AOL
- Complaint feedback loops — high complaint rates = immediate blocking
- Check Sender Hub (previously CFL) at senders.yahooinc.com