I got on my outlook this morning and received a "High-Severity Alert" User restricted from sending email.

Question

I got on my outlook this morning and received a "High-Severity Alert" User restricted from sending email.

Jeff Nowaczyk 0

Good morning,

For some reason, I received a a lot of "undelivered emails" to my inbox this morning. I never sent out a mass amount of emails, but they received them like I did. Shortly thereafter, I received a "High Severity Alert: User restricted from sending emails" notification. So now when I try to send out an email, it will be sent directly back to me. I'm able to receive them, just not able to send any. Please let me know what to do. Thank you!

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Answer 1

Hi Jeff,

I hope you’ve been well, I appreciate you sharing what happened.

Based on the unexpected undeliverable messages and the “User restricted from sending emails” alert, your account may have generated suspicious outbound email activity. As a protective measure, Microsoft 365 may have temporarily restricted the account from sending messages, which explains why you can still receive emails but your outgoing messages are being returned.

As an immediate precaution, if you can still access your account, please change your password to a new and unique password by:

Signing in to https://myaccount.microsoft.com
Select My Account > Change Password from the left-hand menu
Entering your current password, and then creating and confirming your new password.

After changing it, I recommend contacting your organization’s IT administrator as soon as possible. They can help secure and restore the account by:

Revoking active sign-in sessions.
Reviewing recent sign-in activity, mailbox rules, forwarding settings, connected applications, and sent messages for anything unfamiliar.
Ensuring multifactor authentication is enabled.
Checking the account under Email & collaboration > Review > Restricted entities in the Microsoft Defender portal and removing the sending restriction after the account has been secured.

Please avoid repeatedly attempting to send emails until the account has been reviewed, as the underlying suspicious activity should be addressed before the restriction is removed.

In case you do not know who is your IT admin, kindly refer to this article: How do I find my Microsoft 365 admin? - Microsoft Support

I hope this information helps point you in the right direction. Should you have any further questions or need additional assistance, please feel free to share them in the comment below. I'm very happy to help.

If the answer is helpful, please click 'Yes' and kindly upvote it.

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