Sometimes the Pictures image folder on the server is moved to an external hard drive for space reasons and linked via drive letter .
Thereby 3 problems can occur:
The problem occurs only for the administrator login. Add the following key to the registry:
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies\System\ EnableLinkedConnections=1
To do this, the service must be started with a login that is also allowed to see the mapped drives. If problem 1 was solved, then this can also be the administrator login.
There possibly helps the release of the image path in the network and the direct connection from the client over menu [Options|OnyxServer|Status Information].