Connection Problems - DirecTV

I have the main receiver in my family room and a mini in each of two bedrooms. One of the minis in the bedroom will not connect. When I turn it on, it starts the process and then the DVR shuts off. It stays on less than a minute. The main receiver shows that one mini is connected (wired) and the other is shown as not connected> Help!
Incidentally, I always though the DirecTV had the best customer service on the internet. Not anymore. As much as I hate it, I may have to return to cable.

This question, "Connection Problems," is about DirecTV channels, programming, equipment, and sports.