Bugging when "power sensor found" trying to switch 1 sensor to another

My Garmin Edge 1040 is bugging out (once again). This time it has been stuck for a few days with: "power sensor found". I can’t get out of this situation; whether I press X or V, it always comes back to that. I can’t even save the 'ride' I started, or go back to the main screen. Any solution?