WN2000RPT no internet access thru ATT U-verse Router

I'm hoping someone can help guide me in finding a solution to my problem. I purchased a netgear repeater a couple months ago to extend wireless internet coverage to my home (the ATT U-Verse router failed to provide full coverage in my hom). I was able to set up and use the repeater for the most part (with a few instances where it would myseriously lose connection), but as of this past weekend, it has stopped providing internet access completely. I am able to log onto the network no problem, but there is no internet access??

So far, I've updated the netgear firmware, reset the network using the setup wizard, reset the extender to factory settings, reset the ATT router...nothing works. Any suggestions? I'd appreciate any help I can get. Tried calling Netgear and ATT support but they were pretty useless...with Netgear being the worse of the two.