Windows Client can't delete local folder

Another user deleted a folder on an external storage share. That was intentionally and ok.
On the server it is gone. But my Windows client (3.3.3) now says it cannot delete that folder locally on my machine (W10). Even I cannot delete that folder manually in the windows explorer. No error. Simply nothing happens.

I already stopped the NExtcloud client and rebooted the machine and tried again. No success.
There are 2 subfolders in that folder. Cannot delete them. There were some files in that folders. The files were gone/synced away by the client obviously. The user permissions of that folder (in Windows Explorer) look like other folders on that share do.

I can create a new folder in the same parent folder in that share. And I can delete that one. But Windows explorer gives me an unspecific error (“unknown error”) on the deletion. But after confirming, the folder is gone.

I am not shure if this is a Windows problem (no such problems so far) or a problem with the Windows Nextloud client. Or mixture…

Any help is appreciated. Thank you very much!