WAN issue on GL-AR150 with PoE

I have two identical GL-AR150 External Antenna with PoE. Providing PoE over the WAN port works fine, but the WAN port almost never is recognized to transfer data or if it is then usually just for a few seconds. This is identical on both units and is independent of whether I supply power over the WAN-PoE port or by USB. Am I doing something wrong or do you have any tips on how to narrow down the problem?

Thanks, Daniel

What is the model of your PoE adapter?

This should not happen.

I use a PoE Switch Netgear GS11oTP. The PoE standard is IEEE 802.3af (DTE Power Via MDI). Please note that the GL-AR150 WAN port doesn’t seem to work properly for Ethernet connections (anymore?) even when connected to a non PoE port.