MS Support?

I show Office 2021 End of Support as October 13, 2026
End of support for Office 2021 - Microsoft Support

Chat Support:

Open a browser to Contact - Microsoft Support
Tell us your problem -> "Outlook 2021 IMAP Sync"
[Get Help], {Scroll down to the bottom of the page}, [Contact Support]
Sign in with any Microsoft account.
Products and services -> "Microsoft 365 and Office" -> "Outlook", [Confirm]
Choose a support option -> "Chat with a support agent in your web browser"

Post your question on the Microsoft Q&A Forum:

Outlook - Microsoft Q&A
(Please put a link to your Q&A post here, so the rest of us can follow).