Hi @Maciej Morawiak [Ext] ,
Did you install other Office applications before?
Did this problem appear for open history version document?
I suggest you check the credential prompt dialog box title and check if it is Windows credential or Web credential.
Go to Control Panel- Credential Manager- and check if you can find any related credentials for Windows credential or Web credential, try to remove them and test again.
Any updates please let me know and I'm glad to help you.
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