@mc-T2

Yes, I have successfully upgraded the gateway previously without problem.
I have tried uninstalling everything (mcStudio, mcOTA, drivers, etc.) and reinstalling (including reflashing the device with a USB key) and the gateway still doesn't connect to the mcDongle (regardless of whether I specify the ID or not).

I can confirm that the gateway is definitely connected to the network as I can see it show up and disappear in the list of devices on the router, so it's successfully getting an IPAddress.