Email delivery failures

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Posted on by CharlesPP

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Hello,

I manage a flow Power Automate which sends approximately 70 e-mails every day, but I receive in Outlook non-delivery errors indicating that the sender address is not recognized as valid.

Here is the error : "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."

Has anyone experienced this problem or have any tips to share to resolve this situation?

Thank you for your help !

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Expiscornovus 33,195 Most Valuable Professional on at

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You (or somebody with admin permission in your org) could check if your user is listed on the Restricted entities page (and remove it from there).

The below Microsoft article demonstrates a couple of approaches:

https://learn.microsoft.com/en-us/defender-office-365/outbound-spam-restore-restricted-users?view=o365-worldwide

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Michael E. Gernaey 53,362 Super User 2025 Season 2 on at

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Hi

Can you please share your flow, and specifically a Flow Run, with the input Properties and also the raw input properties to the Send Mail Action please.

This could be a spam issue as EXpiscornovus said, or it could be a mistake in the flow.

The error alone is not enough to diagnose the issue for sure

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