Microsoft (Outlook.com and Microsoft 365) · permanent error
550 5.7.240: HVE: application not allowed
The application used to send is not authorized for HVE accounts, so Exchange Online rejected the message.
- Microsoft
- Provider
- Permanent (5xx)
- Class
- Sources checked
- Author
At a glance
- Code
- 550 5.7.240
- Temporary or permanent
- PermanentRefused for good: the message comes back to the sender, and resending it gets the same answer.
- Who has to act
- The sender. The fix is on the sending side: your domain, your server or your list.
- What the server says
550 5.7.240 The application is not allowed for use with an HVE account.
What it means
Exchange Online returns 550 5.7.240 when the application submitting a message is not authorized for use with HVE accounts. The account itself may be set up correctly; the refusal concerns the client using it. Microsoft points admins to its guide on configuring an application or device to send with HVE, so compare the application's setup, including how it authenticates and which endpoint it uses, with those steps.
Common causes
- The application is not authorized for use with HVE accounts.
- The application connects or authenticates in a way HVE does not accept for that account.
How to fix it
- 01Admins: review the sending account's configuration in Microsoft's HVE setup guide.
- 02Confirm the application uses a supported authentication method and the HVE endpoint.
- 03Retry from the application once its setup matches the guide.
Sources
What this page rests on, checked on 20 Oct 2026. The explanation is ours; the reply text is the server's.
- Email nondelivery reports and SMTP errors in Exchange Onlinelearn.microsoft.com
- Manage High Volume Email for Microsoft 365learn.microsoft.com
Related codes
Further reading
All 111 Microsoft codesEvery code in the wikiPaste your own bounce