Are you admin or end user?
If you are an end user contact your admin for further help. For an admin refer to the article: https://learn.microsoft.com/en-us/defender-office-365/outbound-spam-restore-restricted-users?view=o365-worldwide
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I have problems sending mails. Its showing me ''This message couldn't be delivered because the sending email address was not recognized as a valid sender.''
Are you admin or end user?
If you are an end user contact your admin for further help. For an admin refer to the article: https://learn.microsoft.com/en-us/defender-office-365/outbound-spam-restore-restricted-users?view=o365-worldwide
Hi @Arbnor Nikaj
Welcome to our forum!
Agree with NoOneCan.
As i know, the error message you received indicates that your email address is suspected of sending spam and is no longer allowed to send messages outside of your organization.
In addition, i find a similar thread you may feel free to refer to.
Hope it helps.
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