If you have a network license, you can use the Arnold License Manager to connect to the network license server.
Open the Arnold License Manager
If you see a Server list is currently overridden message, that means the ADSKFLEX_LICENSE_FILE environment variable is set, and Arnold is using ADSKFLEX_LICENSE_FILE to connect to the license server.
If you want to use the Arnold License Manager to connect to a license server, you'll need to clear the ADSKFLEX_LICENSE_FILE from your system.
If necessary, click License and then click Network (if you have an annual subscription license from Autodesk) or RLM (if you have a monthly network license from Solid Angle)
In the Add License Server dialog box, type the name or IP address of the license server in the Host text box.
You don't have to add an @ symbol before the name (but if you do, that's ok too).
You can leave Port empty, unless you've been told to use a specific port number (for example, if your IT team is using a specific port to get through a firewall).
Click Ok and you'll see the status of your single-user license. Happy rendering!