Mini box remote no longer powers on/off

URC 2220-R remote can no longer power on and off the TV.  All other functions work and it has previously worked since I got the mini box.   I have 2 other mini boxes and this remote cannot power up them either.  These other 2 remotes also cannot power up the first TV.   Therefore, not clear whether the problem is with the remote or the mini box.   Thanks for any assistance.