Use this as a first-pass decoder before going to the detailed module sections.
SMTP Errors #
| Code or Pattern | Meaning | First Fix |
|---|
421 | Mail server temporarily unavailable | Retry later and check provider status |
450 / 451 | Temporary mailbox or provider issue | Retry later; reduce send volume if needed |
535 / 5.7.1 | Authentication failed | Re-enter credentials or regenerate the key/password |
550 / 5.1.1 | Sender or recipient not accepted | Verify sender identity and recipient address |
552 | Message too large | Reduce attachment size |
554 | Policy, spam, or reputation rejection | Review SPF, DKIM, DMARC, sender reputation, and content |
WhatsApp Errors #
| Error or State | Meaning | First Fix |
|---|
| Template rejected | Meta refused the template content or category | Review the rejection reason and resubmit |
| Session expired | More than 24 hours since the last inbound customer message | Reopen the conversation with an approved template |
| Phone not connected | The WhatsApp number is disconnected in Meta | Verify phone status in WhatsApp Manager |
| Message failed to send | API or delivery issue | Check number format, template approval, and Meta status |
API and Integration Errors #
| Code | Meaning | First Fix |
|---|
401 | Missing, invalid, or expired authentication | Recheck token and authorization header |
403 | Feature, scope, or permission denied | Confirm plan, role, or token scope |
429 | Rate limit reached | Back off and retry later |
Where to Go Next #
