解决office365无法登录以及同步的问题

You better need to test them one by one.

Trick1

win + R -> cmd -> regedit -> "path" ComputerHKEY_CURRENT_USERSoftwareMicrosoftOffice16.0(this may different)CommonSignIn, set value data as 0 , where name is SignlnOptions.If don't exist, new key.

Trick2

I went to Settings -> Accounts -> Access Work or School. And I hit "Disconnect" on her company Work or School account. This deletes the saved Office 365 / Azure AD account from the machine.
After that, when I went into Word -> Office Account I see the yellow message below. "Can't display online services. Sorry, we had a server issue and can't display your connected services. Please try again."
When I clicked on Try again, it then pulled up a different looking sign-in window and it walked me all the way through the sign-in process include email address and password. (It also prompted me to add a phone number and a PIN, I think because Azure AD had some new security requirements.)

Trick3

Trick4

Eventually, I sincerely appreciate the official help.

Reference

http://www.jasonhartman.net/2019/03/office-365-cant-display-online-services.html
https://docs.microsoft.com/en-us/office365/troubleshoot/administration/connection-issue-when-sign-in-office-2016
https://answers.microsoft.com/en-us/msoffice/forum/all/office-365-sign-in-problem-0xcaa30194/e5b398de-9a2e-4f29-be58-6214394152d3
https://answers.microsoft.com/en-us/msoffice/forum/all/under-connected-services-it-says-cant-display/d7c9c857-8095-4c2c-bd87-feae336e08ce