@Kevin_Z I reseted the 901 once again and tried different connections, with and without a switch in between. To connect the 901 directly to a LAN port of the router did the trick as it seems. Still...

@Kevin_Z Thank you. It seems I can't fix this. I had a look at router's protocoll, it stated an issue with IP address allocation (when the devices try to connect I guess). At the moment I can't reach...

Hello, yesterday I received the TL-WA901ND. It's connected via LAN cable to a switch, the switch is connected via LAN cable to a Speedport router (router's IP address is 192.168.2.1, DHCP enabled)....