Stick up cam Elite has "poor connection" over PoE -- how?

I just installed a couple of Stick up cam Elites, using PoE. \*Both\* of them either can't connect because the "connection is very weak", and if it does connect, it says "Poor connection" at the top of the live view. How is this possible using Ethernet? I did select Ethernet during setup. I did \*not\* select WiFi.