2007 Chevy Avalanche Key Fob

I have 2007 Chevy Avalanche. All of a sudden when I exit the vehicle I can lock the truck with the key fob. After about 5 mins. The key fob will not work to unlock or lock or start or even the panic button does not work. This is same on both fobs. I did replace the batteries on both fobs and still no response with either fob.

Would appreciate a little help if anyone have any. Dont really have the time to go spend in the dealership if its something I can do myself.

Thanks
Greg