Hello @Arnolex,
As Mike suggests, try another Cat5e (Or higher) cable, make sure this is STP cable.
Make sure you are on the latest Firmware version for QU V1.97, if not, please update.
If you have access to another QU console or another AR/AB rack, troubleshoot connecting devices to identify where the fault resides.
Example:
Connect another rack to the console, if this works, then we can confirm that the console and its dSnake port are working fine, if this second rack fails then the problem might be in the QU unit.
Connect your AR2412 to another QU or SQ console, if this works, then we can confirm that the rack is not the problem, if it fails then it is likely that the rack has a hardware issue.
If you need further assistance, feel free to contact A&H Support team at: Support@allen-heath.com
For servicing your failing unit (After identifying which one is failing), please contact your nearest A&H distributor partner: https://www.allen-heath.com/where-to-buy/
Cheers,
Rafael