An integrated threat protection solution designed to detect, investigate, and respond to cyber threats across Microsoft 365 services.
Thank you for letting me know.
Since Repair and Reset did not fix it, please uninstall the Microsoft Defender app first, then reinstall it from the Microsoft Store.
After reinstalling, open Microsoft Defender again and click "Sign in" under the notice shown on the screen.
Let me know exactly what happens after you click "Sign in," including any error message you get.
Thanks!