Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
Hii,
I am sorry, but regarding your issue, it is not possible to use Office 365 on macOS High Sierra (10.15) for editing and saving files.
It was announced that, as of July 13, Office 365/2019 is no longer compatible with editing and saving functions on Macs running versions prior to 12.7.6 (Monterey).
You can find instructions on using Office at the following link. This requires a newer version of macOS.
In your case, you can only view and print files in Office 365.
You can also try Office for the Web, which is free:
https://www.microsoft.com/de-de/microsoft-365/free-office-online-for-the-web
I am sorry; I wish you a pleasant week.
Regarding error 0x0, please try the procedure described below or uninstall and then reinstall Office.
Download version 16.65: https://learn.microsoft.com/en-us/officeupdates/update-history-office-for-mac
Please rate this question and visit the Microsoft Q&A community if you have further questions.
Thanks