I had this happen too. I have 4 appletv 3s and it only happened on two of them. These were both on Ethernet and the two unaffected were on wifi.
Resetting/restoring didn't work for either. Using the reset settings using my phone as a hotspot worked to fix one and not the other. Then after resetting the last one one more time when switched back to Ethernet, finally worked. I hadn't read this until today and didn't try the Namibia trick. I think I tried one other country without success in addition to resetting airport and my dsl modem as well....
Annoying
Resetting/restoring didn't work for either. Using the reset settings using my phone as a hotspot worked to fix one and not the other. Then after resetting the last one one more time when switched back to Ethernet, finally worked. I hadn't read this until today and didn't try the Namibia trick. I think I tried one other country without success in addition to resetting airport and my dsl modem as well....
Annoying