Cannot Access Network Share from Windows 10 over VPN

Usually, I connect to a remote server over vpn and access files by typing \192.168.1.1\c$ in the explorer, or use xcopy with the ip and folder as source path.

Now I get the error code 0x80004005 - unknown error from explorer and invalid path from xcopy.

ping to ip adress works. Rdp access also works fine.

Except Windows Updates nothing has been changed to either side (client and server).

How can I fix this? What would be the next thing to analyse along the way?

update 1:

net use * /delete did not solve the issue

net use Z: \\192.168.1.1\c$ returns error 53

update 2:

Updating to Windows 10 20H2 (19042.685) did not solve the issue

update 3:

enabling smb client did not solve the issue

Disabling Bitdefender Firewall did solve the issue.