Prerequisites
The USB-C Extension over CAT receiver must be installed and an RJ-45 cable must be selected. For more information, see:
The USB-C Extension over CAT receiver must be installed and an RJ-45 cable must be selected. For more information, see:
The USB-C Extension over CAT kit includes two ‘USB-C’ cables. Each cable is designed for one of the USB-C Extension over CAT devices:

USB-C cable with a screw lock on both connectors
Connect the ‘USB-C’ cable to the ‘USB-C’ port (reference 1) and tighten the screw lock (reference 2).

Install the other end of the ‘USB-C’ cable.
Connect the selected RJ-45 cable to the HDBaseT port (reference 3).

Is the USB-C Extension over CAT transmitter installed and connected?