HOW DO I FIX MY UNDELIVERABLE EMAILS. EVEN MY ACCOUNT EMAIL ADDRESS IS NOT RECOGNIZED.

Israel Velazquez 0 Reputation points
2026-09-07T18:47:54.6833333+00:00

All my send out email is returned as undeliveragle.

I send out the same emails every Monday. This is the first time all have been returned. I tried both the classic and the ordinary, but the same results. See the following:

[Moderator note: Personally Identifiable Information removed]@iwvministries.com]

"This message couldn't be delivered because the sending email address was not recognized as a valid sender. The most common reason for this error is that the email address is, or was, suspected of sending spam. Contact the organization's email admin for help and give them this error message."Did not even recognize my email address.

Outlook | Windows | Classic Outlook for Windows | For business
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  1. Kai-L 18,725 Reputation points Microsoft External Staff Moderator
    2026-09-07T19:12:53.87+00:00

    Dear Velazquez,

    This error does not mean your email address no longer exists. It is the 5.1.8 "bad outbound sender" condition, which means Microsoft 365 has temporarily restricted the mailbox from sending because it exceeded outbound sending limits or was suspected of sending spam. You can still receive mail while this is in place. An admin will need to lift the restriction. If you manage the domain yourself, you can do this, otherwise please pass this on to your IT admin.

    • Sign in to the Microsoft Defender portal
    • Open Email & collaboration > Review > Restricted entities.
    • Search for the affected mailbox.
    • If listed, select it and choose Unblock.

    Before unblocking, the account should be secured:

    • Reset the account password.
    • Revoke active sessions.
    • Enable or verify MFA.
    • Check for unknown Inbox rules, forwarding addresses, delegates, and sent messages.
    • Scan the computer for malware.
    • Review whether an application or mailing tool sent an unusually large number of messages.

    After removal from Restricted entities, it can take some time before sending works again, commonly up to about one hour.

    Do not repeatedly resend the Monday emails until the account has been secured and unblocked, as further attempts could extend the restriction.

    For reference: Remove blocked users from the Restricted entities page - Microsoft Defender for Office 365

    If the mailbox is not shown in Restricted entities, your IT admin can open a support request with Microsoft. A technical support engineer can perform a remote session to investigate the situation, verify the backend configurations, and run any necessary synchronization tools to resolve the problem. If the issue requires further attention, they can escalate it to a specialized team for deeper analysis. For detailed instructions on how to get support, please refer to Get support - Microsoft 365 admin. If you don't know who your IT administrator is, please refer to this article: How do I find my Microsoft 365 admin? - Microsoft Support 

    I hope this information helps clarify the situation and provides you with a clear path forward. Should you have any further questions or need additional assistance, please don't hesitate to reach out. I'm always happy to help. Have a wonderful day! 

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