How to Rebuild Low Domain Reputation and Fix Deliverability

Domain reputation works like a credit score for your sending domain. When it drops, providers like Gmail, Outlook, and Yahoo block, defer, or quarantine your messages. Recovery is methodical: verify authentication, monitor reputation, audit performance, and warm volume back up gradually.

Bounce Messages That Signal Reputation Problems

Gmail Reputation Blocks

• The sending domain has a very low reputation, causing Gmail to block the message as suspicious or spam
• The sending domain has a poor reputation, causing Gmail to block or defer messages as potential spam

General Reputation Issues

• The sending domain has a poor reputation, causing the recipient's mail system to reject the message

Blacklist Issues

• The sending domain is blacklisted by Spamhaus
• The sending domain is listed on industry blocklists
• The sending domain is blacklisted by reputation services like Spamhaus or Abusix

What Drives Domain Reputation

• Domain age — domains under 3 months old are viewed with suspicion
• Authentication status — missing SPF, DKIM, or DMARC severely damages reputation
• Engagement metrics — low open rates, high bounces, and complaints all hurt
• Sending patterns — sudden volume spikes and irregular schedules trigger penalties
• Content quality — spam-like wording and misleading subject lines compound the problem

Reputation Score Bands

• 85-100 — Excellent. High inbox placement.
• 70-84 — Good. Mostly inbox, some Promotions tab.
• 50-69 — Fair. Mixed inbox and spam placement.
• Below 50 — Poor. Mostly spam folder or blocked.

Step 1: Verify Authentication

1. Go to Settings → Email Services → Dedicated Domain and IP.
2. Click Verify Domain.
3. Confirm all records (SPF, DKIM, MX, CNAME, DMARC) show as verified.
4. If any fail, follow the DNS instructions and wait at least 2 minutes for propagation.

Step 2: Monitor Reputation Externally

• Google Postmaster Tools — set up at postmaster.google.com. Shows domain reputation, spam rate, and authentication data for Gmail. Essential because Gmail represents 60%+ of most lists.
• Sender Score — free 0-100 reputation score at senderscore.org. Below 70 indicates trouble.
• MXToolbox Blacklist Check — scans your domain across major blocklists.

Step 3: Audit Performance

Go to Marketing → Email → Statistics and review:

• Delivery rate — should be above 95%
• Open rate — should be above 20%
• Bounce rate — should be below 2%
• Unsubscribe rate — should be below 2%

If delivery rates drop while bounce rates stay flat, mail is likely going to spam due to reputation. Review Settings → Email Service → Bounce Classification for patterns.

Step 4: Test Inbox Placement

Manual Seed Testing

1. Create test accounts on Gmail, Outlook, Yahoo, and Apple Mail.
2. Send campaigns to those accounts.
3. Check inbox vs. spam folder placement.
4. Document placement rates per provider.

Third-Party Tools

• Mail-Tester.com — free spam score testing
• GlockApps — full inbox placement testing
• EmailOnAcid — deliverability and rendering

Step 5: Warm Sending Back Up

• Start with your most engaged segment (opened or clicked in last 30 days).
• Increase volume gradually — roughly 25-50% per day if engagement holds.
• Suppress unengaged contacts (no opens in 90+ days) until reputation stabilizes.
• Send on a consistent schedule rather than in unpredictable bursts.