Catalina will not load external USB Harddrives over the network

[roelwelters]

The usb drives are connected to a mac mini, mounted in catalina and are accessable from the machine with the drives attached.
When this machine is approached over a lan the all drives are listed, internal and external.
Internal drives can be browsed remotely but when an external drive is selected I get the message:

I have a second machine with the exact same configuration and that works fine.
I've tripple checked permissions.

Regards