An error occurs even when THERS account is entered at the time of sign-in.

Q. An error message appears when signing in to Microsoft 365 Copilot with a THERS account(ab.12c.3456@f.thers.ac.jp, @s.thers.ac.jp, @a.thers.ac.jp): "We couldn't find a Microsoft account. Try entering your details again, or create an account.".

A. It is possible that the user is attempting to sign in to the personal or home edition of Microsoft 365 Copilot.

*From January 2025, the name "Microsoft 365" was changed to "Microsoft 365 Copilot".

1. Click the link below. The sign-in screen for the Tokai National Higher Education and Research System will be displayed.
   https://myapps.microsoft.com/?whr=thers.ac.jp
    
2. Enter THERS account(ab.12c.3456@f.thers.ac.jp, @s.thers.ac.jp, @a.thers.ac.jp) and password.
    
3. Click the user icon in the top right corner of the screen. If the THERS account is displayed in the account information, the sign-in has been successfully completed.
   

There are two types of Microsoft accounts.

• Microsoft account

  Microsoft accounts are for personal use and can be created for free.

• Microsoft work or school account

  Microsoft work or school accounts are Microsoft 365 accounts issued by your organization.

  A THERS account is a Microsoft work or school account, so the Microsoft services used with a THERS account are also intended for work or school use.

Reference : What's the difference between a Microsoft account and a work or school account?