Hi @Vishvajit Das,
What version of Office did you use?
Did you use the Office 365?
I suggest you try to remove the Office credentials and test if you can sign in again without problem:
- From Start, type credential manager, and then select Credential Manager from the search results.
- Select Windows credentials.
- If there are any credentials for MicrosoftOffice16, select the arrow next to them and then select Remove.
- Close Credential Manager.
- From Start, select Settings (the gear icon) > Accounts > Access work or school.
- If the account you use to sign in to office.com is listed there, but it isn’t the account you use to sign in to Windows, select it, and then select Disconnect.
- Restart the device and try to activate Microsoft 365 again.
Please provide more information about the problem and I’m glad to help and follow up your reply.
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