Your boiler's control panel detects that one of the buttons is jammed or held down, which is preventing the system from operating normally.

DIY fix possible

Turn off the electrical supply to the boiler at the fused spurInspect the front control panel buttons for any debris, dirt, or signs of being physically stuckGently wiggle and press each button multiple times to see if they release and click freelyTurn the electrical supply back on and check if the error is cleared