C6 Won't Recognize Fobs. Anyone know about this problem?

[Scale-Master]

2007 C6 with 35,000 miles, almost no problems. Put gas in it like usual and the car would not unlock afterwards. After fiddling with the fob it unlocked only to lock again and not work further. Went home and grabbed the other fob, same thing, not recognized.

It did this once before several months ago, but it only lasted a few minutes so it was assumed to be an interference issue, (it was in a parking structure).

Has anyone had experience with this problem? Any idea where to start looking to see what causes this? Is there a "reset" trick? Any help or suggestions are appreciated.