Since I only have this problem on two MX-Linux-KDE machines, I guess it’s a MX-Linux problem. Though on their forum I didn’t get a reply by now.
On one machine I run two instances, one is version 3.0.2 (KDE), the other one version 2.5.1git - the same problem on both of them.
Anyone an idea about this?
Same problem for me with Endeavour OS and i3WM. No idea what it is. Maybe related with folder permissions? So nextcloud client is not capable of writing the file with the keyring or something like that?
I had the same problem with endeavour os and it turned out the missing keyring was the cause. I fixed it with yay -S gnome-keyring , but i think any keyring will do.