Could be a software or hardware issue or physical damage, try updating the software/firmware, if that doesn't work then you can try checking cable connections or perform, factory reset.

Setup ArtNet on Avolites Arena: Access the settings or network configuration menu on the Avolites Arena console. Locate the ArtNet settings. Ensure that ArtNet is enabled and configured properly. You may need to set the IP address and subnet mask according to your network setup. Connect Avolites Are...