I think you are in the wrong section for complaints about licensing. This is a pretty nice forum and if you ask nicely, you usually get help here. I also had issues with licensing and had contact to an Autodesk Agent via chat and they even called me on my phone to resolve my issue. Do you really think that someone is willing to go the extra mile to help you with your problem if your headline is "your support sucks"?
just my 2 cents here.
Assuming you're using a recent version, use the Arnold License Manager to install the license server: click File > Install License Server
Then click License > Switch to Network Licensing and connect to the license server:
https://docs.arnoldrenderer.com/display/A5AILIC/Connecting+to+a+Network+License+Server
Stephen, thank you very much, but I've already tried that and it didn't work, that's why I wrote to support. But... there is silence since 3 days from them...
Kyan, I did everything as you did, but imagine that support didn't resolve my issue. Why? Because they don't answer my emails! And yes, you're right - I'm in the wrong section...