Cannot access tresor on network devices

I use Macos 10.15.5 with Cryptomator 1.5.5.

I have a few tresors on smb-network-devices served by a mac-mini which worked fine in the past. Now I can open them with cryptomator but I don’t have any rights to access.

When I coy the tresors to local storage (SSD), accessing them is no problem. But that is no solution for me. What can I do do work with tresors on network-devices, like in the past?