In the end I see no other solution than to try a fresh reinstallation.
Regarding to this posts…
… I am worried about how to completely uninstall webtop5 in order to try a completely new installation.
Within the NextCloud documentation, there is a wonderful description of how to manually carry out a residue-free uninstallation. Unfortunately, this is missing at webtop…as with most others.
@webtop_team: Can anyone guide me through such a complete uninstallation of Webtop5?
And by the way, I would appreciate it if all documentation contained a description of the complete manual uninstallation if already an automatic uninstallation should not be possible.