Using Classic Outlook on Windows for personal email, calendar, and contact management
Hi, thank you for reaching out to the Microsoft Q&A forum. I’m happy to help.
Microsoft is experiencing an ongoing service issue that may be causing this problem.
"More info: Users may be experiencing the following issues with Outlook and OneDrive.
Outlook:
-Users may be unable to login successfully or experience delays when attempting to access
-Sending or receiving emails may be delayed or fail to send through any connection method
OneDrive:
-Users may be unable to access OneDrive or experience delays when attempting access
-Users may fail to return user data or receive partial data"
Reference for more details: https://status.cloud.microsoft/m365/referrer=serviceStatusRedirect