Your boiler is having trouble communicating with your thermostat or wireless control system.

DIY fix possible

Check if your wireless thermostat has run out of batteries and replace them if necessary.Ensure the thermostat is within range of the boiler and has not been moved too far away.Try resetting your router or the wireless receiver box attached to the boiler.Follow your thermostat's manual to re-pair or 're-bind' the device to the boiler receiver.