i think it is caused by POE. i suggest you just connect TL-PA211 to your router, the other links to nothing. plug both in sockets, then check with the data is abnormal

i'm not sure about the first question. they recommend plug the adapter directly into the wall socket, and keep big electric applications farther from it. did you do like this? about the printer, i...

i don't know why this happens. but i suggest you connect computer directly to router to check whether it is TL-WPA281's issue. or try another computer with TL-WPA281