I have recently bought a range extender RE650, when I first intalled it following the instructions in Tether it worked fine i.e. I could connect to the internet whilst connected to the range extender then two days later it had stopped working, the extender network was still available and you can connect to it however if you look at Devices whilst connected to the extended network only the RE650 was listed. I ran through the setup again and rebooted the Archer C9, now both devices are listed and I could access the internet again but just a few hours later I have the same issue - the range extender is the only device showing when connected to the extended network and no internet access.

Cheers in advance