4.4.7: Message expired in the queue
4.4.7 means the message sat in the sending queue until it expired without being delivered. The sending server kept retrying, but the receiving server never accepted it in time. This usually points to a problem on the receiving side, but repeated deferrals caused by your reputation end the same way.
The exact messages
Microsoft 365 / Exchange Online
4.4.7 Message expired
Any mail server (RFC standard meaning)
4.4.7 Delivery time expired
Why it happens
- The receiving server was down or unreachable for the whole retry period.
- The receiver kept deferring your mail (for example with 4.7.x reputation deferrals).
- A header limit or protocol timeout on the remote server.
How to fix it
- Check the recipient domain’s MX records.
- Look further up the bounce for the last temporary error; that is the real reason.
- Resend once the receiving server is reachable.
If you send cold email
When many recipients at different domains expire at once, the cause is usually your reputation, not their servers. Look for 4.7.x deferrals in the earlier delivery attempts.
How WarmHawk handles it
A Google Workspace or Microsoft 365 mailbox connected to WarmHawk sends through the provider’s own servers, which already use TLS. A temporary failure is retried with backoff (30 minutes, then doubling, capped at 48 hours) and the lead is suppressed after 4 attempts instead of being retried forever. How WarmHawk works →
Check your domain now
These free checkers read your live DNS: no account, up to 15 domains at once.
Related bounce codes
- 4.7.0Temporarily deferred: low reputation, PTR or TLS
- 4.7.500Access denied, please try again later
- 4.4.2Connection timed out
Sources, checked 2026-09-29: Microsoft Learn: NDRs and SMTP errors in Exchange Online · RFC 3463: Enhanced Mail System Status Codes. Have a different bounce? Paste it into the decoder →
Questions
4.4.7 questions
What does 4.4.7 mean?+
4.4.7 means the message sat in the sending queue until it expired without being delivered. The sending server kept retrying, but the receiving server never accepted it in time. This usually points to a problem on the receiving side, but repeated deferrals caused by your reputation end the same way.
Is 4.4.7 a temporary or permanent error?+
Temporary. The sending server keeps the message and retries it for a while. It only becomes a bounce if every retry fails before the message expires.
How do I fix 4.4.7?+
Check the recipient domain’s MX records. Look further up the bounce for the last temporary error; that is the real reason. Resend once the receiving server is reachable.