How do I troubleshoot block bounces?

• Troubleshooting block bounces requires systematic investigation:
• Step 1: Read the full error
• Extract exact message text. Note any reference URLs or codes. Identify which provider blocked you.
• Step 2: Check blocklists
• Query major blocklists (Spamhaus, Barracuda, etc.). Check both IP and domain. Request removal if listed.
• Step 3: Verify authentication
• Test SPF, DKIM, DMARC alignment. Ensure all sending IPs are authorized. Check for configuration errors.
• Step 4: Review content
• Scan for spam trigger patterns. Check URLs against blocklists. Review recent campaign content.

• Step 5: Check reputation tools
• Google Postmaster Tools. Microsoft SNDS. Provider-specific dashboards.
• Step 6: Follow remediation

Many block messages include remediation URLs. Follow provider-specific processes.

Block bounces are symptoms. Find and treat the underlying disease.