S1 failing to connect to Windows PC properly

[classic-goldbug]

I've been struggling to get my new S1 up-and-running for the past few days now. It seems to have some real problems with the ethernet connection on my PC but I'm at a loss as to how this might be resolved.

This morning I was able to plug it into my Mac Mini, where it connected correctly, and I updated the firmware to the latest version. However, now that I've plugged it back into the PC it keeps experiencing network errors. It will appear briefly in EuControl but if I try to interrogate its firmware version within the application, it says 0.0.0.0 (whereas on the Mac it shows 25.5.0.0). The S1 shows the AVID logo across all screens and does not seem to move on from that as it did when it was connected to the Mac.

It will then disconnect itself. The message this morning is: "Network error - Unable to connect to the unit named "Avid S1 (Avid S1-0C13)". Possible causes: the unit's ethernet or power cable is unplugged, the unit is not powered on, the unit is connected to another network, a bad ethernet cable, or firmware or hardware problems. Check all cable connections, power off the unit for 30 seconds, and try again."

The PC's network setup is as follows:

Ethernet 1: The ethernet adapter on the motherboard, connected via a cable to the Mac with a fixed IP

Ethernet 2: A virtual ethernet adapter for use with GlobalProtect

Ethernet 3: First port of a two-port PCIe ethernet card

Ethernet 4: Second port of the above

WiFi: Another PCIe card, which is connected to the Internet

I've tried the S1 cable (and other ethernet cables) in the Ethernet 1, 3 and 4 ports. I've tried each of these ports with DCHP switched on or with a fixed IP. I've tried disabling all the adapters other than the one I want to use. I've tried plugging in a router and plugging the S1 into that. So far, nothing.

Any ideas?