I did a recent order of a RPi 4, PoE Hat and Neo case from Core Electronics.
I had it running on a Netgear GS108PP, which is also used to power some Ubiquiti G3 Pro cameras.
It appeared to work for a couple of days. Now every time I plug it in, the RPi red LED flashes and emits a small beep which I understand is a voltage issue. Absolutely nothing has changed, and no-one has bumped it as it’s a high shelf out of everyone’s reach.
If I reconnect it via USB-C everything is perfect again.
Any thoughts on how to diagnose? I don’t have a multimeter and as we can’t have home visitors with COVID restrictions, I can’t have a friend over to diagnose just yet.