I had similar problems with my AR7000 receiver. After about 3 days of use it just started failing to establish a connection. At first rebinding helped but after playing with it a bit more trying to figure out what happened it was occuring more and more. In the end it was failing range tests and only actually connecting with the transmitter about 1 in 5 tries, so I sent it back and it was replaced no questions asked.

May be a completely different issue with yours, but it's worth keeping an eye on. I'm lucky I like to figure out what causes problems or I may have tried to fly and had an in-flight failure.