TABLE OF CONTENTS

• What's Happening?
• Quick Diagnosis: Identifying Mail Loop Issues
• Understanding Mail Loop Causes
• Step-by-Step Mail Loop Resolution
• Advanced Resolution Techniques
• Prevention and Best Practices
• Recovery Timeline and Expectations
• Monitoring and Maintenance
• Working with Support
• Success Indicators
• Still Having Issues?

Mail Loop Detection Issues - Complete Troubleshooting Guide

What's Happening?

Your email gets trapped in an endless routing cycle between mail servers, creating an infinite delivery attempt cycle. Mail servers detect this pattern and reject the message to prevent system overload. This prevents delivery and can impact your sender reputation if not resolved quickly.

Mail loop detection occurs when email forwarding rules, MX record configurations, or automated responses create circular routing patterns. Unlike other delivery issues, mail loops require immediate attention as they can quickly escalate and affect your entire sending infrastructure.

Quick Diagnosis: Identifying Mail Loop Issues

Look for these bounce messages that indicate mail loop problems:

Common Loop Detection Messages

• The message was rejected because it was caught in a routing loop between mail servers.

Understanding Mail Loop Causes

Common Loop Scenarios

Specific Considerations

Step-by-Step Mail Loop Resolution

Step 1: Immediate Diagnosis

Check your domain configuration:

1. Navigate to Email Services:
   • Go to Settings → Email Services → Dedicated Domains and IP
   • Check for any warning indicators or incomplete setup steps
   • Verify domain authentication status
2. Review recent changes:
   • Check if you've recently modified email forwarding rules
   • Review any new workflow implementations
   • Look for changes in conversation email integration
3. Examine bounce reports:
   • Go to Marketing → Emails → Reports
   • Look for patterns in bounce messages
   • Identify affected domains or email addresses

Step 2: External Diagnostic Assessment

For Domain Configuration Issues:

For Email Header Analysis:

• Collect email headers:
  • From bounced emails, copy complete headers
  • Look for all "Received:" lines showing routing path
  • Document repeated server names or IP addresses
• Use header analysis tools:
  • MXToolbox Email Header Analyzer
  • Google Admin Toolbox Message Header
  • Microsoft Message Header Analyzer

Step 3: Configuration Review

Domain Authentication Check:

1. Navigate to Settings → Email Services → Dedicated Domain & IP → [Your Domain] → Authentication
2. Verify SPF record
3. Ensure DMARC policy isn't causing rejection and re-routing

Workflow and Automation Review:

1. Check automation workflows:
   • Go to Automation → Workflows
   • Look for workflows triggering each other in circular patterns
   • Review email-based triggers and responses
   • Identify any workflows that might create reply loops
2. Review email templates:
   • Navigate to Marketing → Emails → Templates
   • Check auto-responder settings
   • Review any automated email responses
3. Examine conversation settings:
   • Go to Conversations → Settings → Email Integration
   • Check email forwarding configurations
   • Review any routing conflicts

Step 4: External Infrastructure Resolution

Eliminate Forwarding Loops:

• Domain registrar/hosting provider review:
  • Log into your domain management panel
  • Review all email forwarding rules and aliases
  • Remove circular forwarding configurations
  • Disable catch-all settings that forward to themselves
• Auto-responder management:
  • Disable auto-responders that reply to automated messages
  • Configure proper filtering to prevent reply loops
  • Set up appropriate sender exclusions

DNS Record Optimization:

• MX record cleanup:
  • Remove duplicate or conflicting MX entries
  • Ensure proper priority ordering (lower numbers = higher priority)
  • Verify all MX records point to valid mail servers
  • Wait 24-48 hours for DNS propagation

Advanced Resolution Techniques

Domain Reconfiguration

When standard fixes don't work:

1. Navigate to Settings → Email Services → Sending Domains
2. Consider removing and re-adding your domain to reset cached routing
3. Ensure all DNS records are properly configured before re-adding
4. Test with small volume after reconfiguration

Campaign Management During Resolution:

• Pause affected campaigns:
  • Go to Marketing → Campaigns → [Campaign Name] → Pause
  • Temporarily halt campaigns experiencing loop issues
  • Prevent further reputation damage
• Document evidence:
  • Collect bounce messages and error logs
  • Save email headers showing loop patterns
  • Track affected domains and volumes

Testing and Validation Process

Small-scale testing:

1. Use Marketing → Emails → Send Test Email
2. Send to various providers (Gmail, Outlook, Yahoo)
3. Monitor email headers for proper routing paths
4. Verify no loop indicators in delivery reports

Gradual campaign resumption:

• Start with small segments of highly engaged contacts
• Monitor delivery metrics closely
• Gradually increase volume while watching for loop recurrence
• Document successful delivery patterns

Prevention and Best Practices

Email Infrastructure Management

• Avoid complex forwarding chains: Keep email routing simple and direct
• Regular DNS audits: Review MX records quarterly
• Test before implementing: Always test forwarding rules with small volumes
• Document configurations: Maintain records of all email routing setups

Specific Recommendations

• Use dedicated sending domains: Separate marketing from operational email
• Monitor automation workflows: Regular review for circular triggers
• Proper unsubscribe handling: Ensure processes don't create reply loops
• Regular health checks: Use our monitoring features

Early Warning System

• Monitor bounce patterns: Watch for sudden increases without campaign changes
• Track delivery times: Unusual delays may indicate routing issues
• Review error messages: Look for "too many hops" patterns
• Recipient feedback: Monitor complaints about duplicate messages

Recovery Timeline and Expectations

Immediate Phase (0-24 hours)

• Pause affected campaigns: Stop loop-generating sends immediately
• Document evidence: Collect bounce messages and headers
• Identify root cause: Determine forwarding or DNS issues
• Begin remediation: Remove circular forwarding rules

Technical Resolution (1-3 days)

• DNS propagation: Allow time for MX record changes
• System cache clearing: Wait for routing information updates
•  Reconfiguration: If domain reset is required
• External system updates: Coordinate with hosting providers

Validation and Recovery (3-7 days)

• Small-scale testing: Verify loop resolution
• Gradual volume increase: Monitor for recurring issues
• Performance stabilization: Return to normal delivery rates
• Reputation monitoring: Ensure no lasting impact

Monitoring and Maintenance

Regular Monitoring Schedule

Daily monitoring:

• Check bounce rates in Reports → Email Performance → Delivery Metrics
• Review any new error message patterns
• Monitor delivery time consistency

Weekly reviews:

• Audit email automation workflows for efficiency
• Review conversation email integration settings
• Check for any new forwarding configurations

Monthly maintenance:

• Comprehensive DNS record review
• Email forwarding configuration audit
• Domain authentication verification

Key Performance Indicators

• Bounce rate: Should remain below 2% for healthy delivery
• Delivery time: Monitor for delays indicating routing issues
• Error message patterns: Track recurring loop-related errors
• Campaign completion rates: Ensure consistent delivery performance

Working with Support

When to Contact Support

• Persistent loop issues: When standard resolution doesn't work
• Domain reconfiguration needs: For complex setup requirements
• Workflow optimization: Advanced automation troubleshooting
• Performance analysis: Detailed delivery metric interpretation

Information to Provide Support

• Specific bounce messages: Complete error text and headers
• Timeline information: When loops started occurring
• Configuration details: Recent changes to domains or workflows
• Affected volumes: Scale and scope of the issue
• Resolution attempts: What you've already tried

Success Indicators

You'll know your mail loop issue is resolved when you see:

• Bounce rates return to normal: Under 2% for healthy delivery
• No loop error messages: Elimination of "too many hops" errors
• Normal delivery times: Under 5 minutes for most providers
• Successful domain delivery: Previously affected domains accepting mail
• Stable performance metrics: Consistent delivery and engagement rates

Still Having Issues?

If you continue to experience mail loop challenges:

1. Double-check all forwarding rules: Ensure no circular references remain
2. Verify DNS propagation: Allow full 48 hours for changes
3. Review workflows: Check for automation conflicts
4. Contact support: Leverage platform expertise
5. Consider professional consultation: For complex infrastructure issues

Remember: Mail loops are technical issues that require systematic resolution. Focus on eliminating circular routing patterns, maintaining clean DNS configurations, and monitoring your automation workflows for potential conflicts.