I had a problem last week with my Devolo 500. Some time ago the upstairs unit stopped working a couple of times but always worked again when I turned off and back on. This time the one in the sitting room stopped working both on wifi and also the dLAN. After a bit of reading up I decided to purchase a Devolo dLAN 1200+WiFi ac from Amazon. I plugged it in and it not only worked straight away but also recognised the older 500 units. Amazingly all the older ones now work but a much higher speed but the WiFi signal is much stronger all around the house.