John
Artnet partch is indeed correct. Since all the other 3 catalysts are visible on the network, then I can assume that the ethernet switch/router is ok too.

The only query I have is - what is the 'Media Server (180) 2.0.0.2' ? is this your Martin dmx-Artnet interface?

If not - then you have a potential artnet clash on universe 9 with a different device - if this device produces artnet. - Change the artnet settings or patch catalyst elsewhere 12+.

If it is your dmx-artnet interface, then fine - but you may want to check its settings to ensure that it is actually converting DMX to artnet.

Check to see if you get communication between the catalyst servers - send a netwerk remote command (if enabled) this will confirm communication. If this works - then the problem points to the DMX-artnet box

Let me know

Simon