On my side, the error has been fixed uninstalling and then reinstalling the OneDrive App.
In doing so, however, I ended up in having the icon of a standard folder for OneDrive
in Windows-Explorer, instead of the OneDrive icon with the clouds.
I then took the further step of definitively uninstalling the OneDrive App and also reinstalling OneDrive in Windows 10.
To do so, I made a search of the file OneDriveSetup in Windows-Explorer under C:
Clicking to open the file
C:\Users\Username\AppData\Local\Microsoft\OneDrive
this has reinstalled the OneDrive, also resetting in Windows-Explorer the right icon of OneDrive with its clouds!. The cloud icon of OneDrive is also back in the Systray,it had disappeared uninstalling the OneDrive App.
Noting how OneDrive is embedded in Windows 10 and the OneDrive App seems therefore not strictly required, I have not reinstalled the App. So far everything work fine.
Note: I did the same procedure on two PCs which we have at home and for both of them the failure has disappeared and the right icon is restored.