Hi thanks for your reply. I have figuered out that there is a possibility that this is a User problem. I tryed another user i have in the system. Witchs mailbox i normally open in this problem user.
I guess that there is a problem becouse i tryed to connect nextcloud to Kopano in this user.
I read that some other people had this problem and fixed it by resetting the Files Plugin configuration but, if i do this the webapp crashes.
I deinstallt the whole webapp from UCS Store and reinstalled it but that didn’t fixed the Problem.
May be you have some other ideas?
ps. i had some reboots of the whole system until now.