Microsoft 365 4.4.7
Message expired
Microsoft 365 4.4.7 means: message expired. It is a temporary failure, so your server retries it. Stop sending from the affected account or IP until the cause is fixed. Check for a compromised account, and remove unverified and unengaged addresses before you resume.
Microsoft 365’s exact wording
Quoted from Microsoft Learn: Email non-delivery reports and SMTP errors in Exchange Online, checked 2026-11-05. Placeholders are Microsoft 365’s own.
Provider's description
Message expired
Possible cause
The message in the queue expired. The sending server tried to relay or deliver the message, but the action wasn't completed before the message expiration time. This message can also indicate that a message header limit was reached on a remote server, or some other protocol timeout occurred during server communication.
Provider's advice
This message usually indicates an issue on the receiving server. Check the validity of the recipient address, and determine whether the receiving server is configured correctly to receive messages. You might have to reduce the number of recipients in the message header for the host about which you're receiving this error. If you send the message again, the message is placed in the queue again. If the receiving server is available, the message is delivered.
| Who sends it | Microsoft 365, Exchange Online and Outlook.com |
|---|---|
| Basic code | Microsoft 365 lists the enhanced code only |
| Enhanced code | 4.4.7: Delivery time expired |
| Permanent or temporary | Temporary (4xx) |
| Verifying the list prevents it | Partly |
In practice
4.4.7 Message expired means Microsoft gave up after retrying for the message lifetime. The real cause is usually on the receiving server: it did not answer, kept deferring, or hit a header limit. Microsoft suggests checking the recipient address and the receiving server's configuration, and reducing the number of recipients in the header for that host.
What the sender should do
Stop sending from the affected account or IP until the cause is fixed. Check for a compromised account, and remove unverified and unengaged addresses before you resume.
Would verifying the list have prevented Microsoft 365 4.4.7?
Partly
The reply is not only about one address, but providers weigh how often a sender hits addresses that do not exist. Removing bad addresses before sending lowers that signal.
Common questions
- What does Microsoft 365 4.4.7 mean?
- Microsoft 365 4.4.7 means: message expired. It is a temporary failure, so your server retries it. Stop sending from the affected account or IP until the cause is fixed. Check for a compromised account, and remove unverified and unengaged addresses before you resume.
- Should I retry after Microsoft 365 4.4.7?
- Your sending server retries it automatically, because it is a temporary (4xx) failure. Investigate only if it keeps coming back over several hours.
- Would verifying my list have prevented Microsoft 365 4.4.7?
- Partly. The reply is not only about one address, but providers weigh how often a sender hits addresses that do not exist. Removing bad addresses before sending lowers that signal.
Sources
- Microsoft Learn: Email non-delivery reports and SMTP errors in Exchange Online (checked 2026-11-05)
- IANA: SMTP Enhanced Status Codes registry (checked 2026-11-05)
Registry and provider wording is quoted exactly; guidance is written by the SimpleVerifier Team.
SimpleVerifier Team · Last checked against the sources 2026-11-05