Errors & Troubleshooting | Updated January 2026
The "central_filter defer (-1): error" message in email bounce notifications indicates that the server's email filtering system encountered an issue processing the message. This is usually a temporary server-side condition.
What to Do
Wait and retry, or contact support
This error is typically transient. Wait 15-30 minutes and try sending again. If the error persists, open a support ticket with the full bounce message so we can check the server's mail filter configuration.
01. Common Causes
- SpamAssassin or email filter overload - The filtering process timed out while scanning the message
- Large attachment - Very large emails take longer to scan and may exceed filter timeouts
- Temporary server issue - The filtering service may have been restarting or under heavy load
- Malformed email headers - Unusual or broken headers can cause the filter to choke
02. Workarounds
- Reduce attachment size - Use a file sharing service instead of large email attachments
- Try sending without attachments to isolate the issue
- Send from webmail to test if the issue is with your email client
For general email troubleshooting, see our Email Troubleshooting Guide.
Error Persisting?
Include the full bounce message in your ticket so we can trace the issue.
Open a Support TicketQuick Recap
- Usually temporary - Wait 15-30 minutes and retry
- Check attachment size - Large files can trigger timeouts
- Test from webmail to isolate the issue
- Include the full bounce when opening a ticket
- Server-side fix may be needed if persistent
Email error troubleshooting · Last updated March 2026 · Browse all Error articles
