Your boiler's internal computer is currently processing data or communicating with an external smart thermostat, which is a normal status check and not a hardware failure.

DIY fix possible

Check your external room thermostat or smart controls are turned up and calling for heatWait up to 10 minutes for the digital handshake between the boiler and controls to completeReset the boiler using the main power switch if the display remains stuck for over an hour