The Konftel OCC hub relies on the DisplayLink technology. 
In Windows 10 the drivers is already included but for MacOS this is not the case.
With newer versions of macOS (BigSur, Catalina), it's important that you use the latest DisplayLink app called "DisplayLink Manager" and not the older "DisplayLink Manager Graphics Connectivity" application.

If you use the older application please uninstall it and install the new app instead.
Detailed instructions can be found on this page: