Your boiler has lost its electronic link to the remote temperature controller, meaning it can no longer receive instructions on when to turn the heating on or off.

DIY fix possible

Locate the Climatic control panel and ensure it is firmly seated in its dock or wall bracketCheck for any visible damage or loose wires at the back of the control panel if it is wireless or battery-poweredSwitch off the power to the boiler at the fused spur, wait 30 seconds, and turn it back on to reset the connection