@ohne I just received the replacement part - a certified and refurbished device from TP-Link. One device is connected to the AP. Packet loss is around 45% after 20 minutes connection time. Since I'm...

TBH I think they dont really care and replacing it, is less work for them. On the other hand we will be able to confirm if it is a software or hardware problem but imho this can’t be software/Visual...

@Spryde TP-Link confirmed to replace my 660HD. I will come back and report if everything is fine with the new device.

@Spryde Unfortunately it is not possible to get in contact to someone at TP-Link. Support tickets aren't replied and telephone support doesn't pick up after 20 minutes.

To exclude any other things, I added a simple wan gateway/router and removed all other devices and VMs. I also removed the AP from the Controller and installed it without a controller. I also changed...

Unfortunaley I was wrong with my suspicion that the problem is vlan related. just added a simple router to the network without any vlans and just the eap 660 shows again round about 40% drop/error....