I bought an AC 750 from amazon. It works as a range extender. However, if I set it up in bridge mode it doesn't work. No internet. Any suggestions. I used the tether app to set it up. At the end I changed it from extender to access point mode. It rebooted. However in this mode there's no internet on the ethernet connection. In extender mode I get no internet on the ethernet connection. 

Any suggestions. I've reset it and tried a few times.