Ring Elite stopped getting power

I've had a Ring Elite for 3.5 years. I power it using PoE. I realized today that it stopped working about 5 days ago-- no power. I checked the power kit and it's working fine-- it's able to power another PoE device (office phone) that I had sitting around. So I pulled out the doorbell from the junction box the and wired it to the power kit using the same wire I checked the phone with. The green power out LED doesn't light up. I tried resetting the doorbell by holding in the main doorbell button and by holding and pressing the black rubber setup button while it was plugged in. Nothing wakes this thing up, and I'm dismayed that the power out green LED won't light (as it did when I tested with the phone). I checked the video history and it doesn't look like it was vandalized and there is no physical damage. It's protected from weather also. Is there any way to wake this thing up or reset it another way? Is there something I should test that I'm not? Or is this thing dead and time to find another doorbell?