Could you please share us with the error message when you couldn't be able to sign in?
Please download and run the license removal tool, then restart your Macbook and sign in again.
Besides, how did you download the Office apps?
It‘s recommended to refer to 'Download and install or reinstall Microsoft 365 or Office 2021 on a PC or Mac', that install Office from account portal.
If the steps do not work, I suggest you add a new user accoun on Mac.
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