4.4.7 Microsoft bounce: message expired
What 4.4.7 means
Exchange Online could not deliver a queued message before its expiry time, which usually points to the receiving server not accepting it in time.
Message text
Message expired
Common causes of 4.4.7
- Receiving server did not accept or relay the message before the queue expired
- A message header limit was reached on the remote server
- Protocol timeout during server-to-server communication
How to fix 4.4.7
- Confirm the recipient domain answers on its MX hosts with MX lookup.
- Reduce the number of recipients in the message header for that domain, then send again.
- If the recipient still does not get the message, ask their administrator to check that the receiving server accepts mail.
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Have the full bounce message? Paste it into the bounce code lookup and it will match the code and the provider for you. Open the bounce code lookup.
How to read 4.4.7
The second part, 4.4.7, is an enhanced status code (RFC 3463 §2) written class.subject.detail. Class 4 is a Persistent transient failure (4xx): the command was not accepted, but the condition may clear, so the sender should try again later (RFC 5321 §4.2.1; RFC 3463 §2).. Subject 4 is network and routing: a problem reaching or routing to the destination. The detail number refines the subject, and providers may define details of their own, which is why one code can read differently at Gmail, Microsoft and Yahoo.
Sending servers should retry a deferred message. RFC 5321 §4.5.4.1 advises waiting at least 30 minutes between attempts and trying for at least 4 to 5 days before giving up and returning a bounce. If the deferral keeps repeating, fix the cause rather than waiting.
Official source: learn.microsoft.com. Last verified 2026-10-20.
Related guides
- How to create an SPF record (syntax and examples)
- How DKIM works and how to publish a DKIM record
- How to set up a DMARC record, from p=none to p=reject
Related codes
- 4.4.1 SMTP: no answer from host
- 4.7.26 Microsoft: ipv6 needs spf or dkim
- 432 4.3.2 Microsoft: recipient thread limit
- 4.5.3 Microsoft: too many recipients
FAQ
What does 4.4.7 mean?
Exchange Online could not deliver a queued message before its expiry time, which usually points to the receiving server not accepting it in time. This is a temporary failure.
How do I fix 4.4.7?
Confirm the recipient domain answers on its MX hosts with MX lookup. Reduce the number of recipients in the message header for that domain, then send again. If the recipient still does not get the message, ask their administrator to check that the receiving server accepts mail.
Is 4.4.7 permanent, and should I retry?
4.4.7 is a temporary failure. Your mail server normally retries by itself; if it keeps repeating, fix the cause.