No Connection to the Server

[Erdo987]

Hello,
I use two Macs.
Main Mac: Mac Studio M1 Ultra, Tahoe 26 operating system
Server: MacBook Pro with Mojave
Both are connected directly via Thunderbolt Bridge, without a hub or docking station.
I entered the IP address and submask manually.
Thunderbolt is lit green, and I can see the server Mac in the network and copy data back and forth.
But Audiogridder can't find the server.
I appreciate any help.
Kind regards