Microsoft 365 550 5.1.241
The message can't be delivered because the recipient is an HVE account
Microsoft 365 550 5.1.241 means: the message can't be delivered because the recipient is an HVE account. It is a permanent failure, so do not retry it unchanged. The fix is in the sending or receiving configuration named above, not in the list. Fix that, then resend.
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
The message can't be delivered because the recipient is an HVE account. HVE accounts do not have associated mailboxes and can only send messages.
Possible cause
The recipient address belongs to an HVE account that's designed for sending only, and it can't receive email messages.
Provider's advice
HVE accounts can't receive messages directly. If you need to have recipients reply to messages that are sent by an HVE account, configure a ReplyTo address for the HVE account so that responses are delivered to a different mailbox.
| Who sends it | Microsoft 365, Exchange Online and Outlook.com |
|---|---|
| Basic code | 550: Requested action not taken: mailbox unavailable (e.g., mailbox not found, no access, or command rejected for policy reasons) (RFC) |
| Enhanced code | 5.1.241: Microsoft 365-specific, not in the IANA registry. Its subject digit puts it under 5.1.0 other address status. |
| Permanent or temporary | Permanent (5xx) |
| Verifying the list prevents it | No |
In practice
HVE, high volume email, accounts in Microsoft 365 are built for sending only. A message to one returns this code because there is no mailbox behind the address. Replies and bounces should go to a different address, such as a monitored shared mailbox. For list hygiene, remove HVE addresses from any list that expects replies.
What the sender should do
The fix is in the sending or receiving configuration named above, not in the list. Fix that, then resend.
Would verifying the list have prevented Microsoft 365 550 5.1.241?
No
This reply is about your sending setup, the message or the receiving system, not about whether the address exists, so verifying the list will not prevent it.
Common questions
- What does Microsoft 365 550 5.1.241 mean?
- Microsoft 365 550 5.1.241 means: the message can't be delivered because the recipient is an HVE account. It is a permanent failure, so do not retry it unchanged. The fix is in the sending or receiving configuration named above, not in the list. Fix that, then resend.
- Should I retry after Microsoft 365 550 5.1.241?
- No. It is a permanent (5xx) failure, so the same message to the same address will fail again. Fix the cause first. The fix is in the sending or receiving configuration named above, not in the list. Fix that, then resend.
- Would verifying my list have prevented Microsoft 365 550 5.1.241?
- No. This reply is about your sending setup, the message or the receiving system, not about whether the address exists, so verifying the list will not prevent it.
Sources
- Microsoft Learn: Email non-delivery reports and SMTP errors in Exchange Online (checked 2026-11-05)
- RFC 5321: Simple Mail Transfer Protocol, section 4.2.3 (reply codes) (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