why won't one Genie (of 4) not respond to remote? - DirecTV

One Genie does not respond to remote. Will control volume up and down, but will not power the Genie off or on, bring up info or guide, or change channels. Will not even bring up menu. Battery light is solid and batteries test good. This is new. Thea Genie has worked normally for 6 months.
Other Genies in the house work normally.

This question, "why won't one Genie (of 4) not respond to remote?," is about DirecTV channels, programming, equipment, and sports.