RC65 Will Not Control Receiver

After today's CHARLIE FOXTROTwith Sunday Ticket, one of my 4 receivers will no longer be controlled by the RC65 that came with it(2 years ago), but it still controls the TV set.  All the other remotes work with the offending receiver.  I have tried multiple resets and many batteries in the RC to no avail.  The main problem of using another remote is that the receiver is in the same room as the HD-DVR receiver and will control both receivers at the same time.  Please advise ASAP.