Q. When trying to sign in to Microsoft 365 Copilot, they receive an error message.
Error: That Microsoft account doesn't exist. Enter a different account or get a new one.
A. Please sign in to Microsoft 365 Copilot using your THERS account such as 'ab.12c.3456@f.thers.ac.jp', '@s.thers.ac.jp', and '@a.thers.ac.jp'.
When signing in, please use your THERS account instead of your THERS email address.
If you are signed in with an account other than THERS account, please sign out.
After signing out, please sign in again from the following site.
https://m365.cloud.microsoft/?auth=2
If you're using a Microsoft personal account, a page with a URL ending in "auth=1" is the sign-in page for that account. Since THERS accounts are for work or school, they cannot be used to sign in from that page.
*Microsoft accounts are for personal use.
*Microsoft work and school accounts are for organizations that use Microsoft 365 Copilot for business.
Reference: An error occurs even when THERS account is entered at the time of sign-in.