Your boiler is currently taking a temporary rest because it has reached its target temperature and is waiting for the water inside to cool down slightly before firing up again.

DIY fix possible

Check if your room thermostat or TRVs are set too low, causing the boiler to reach temperature quickly.Ensure at least one or two radiators are fully open to allow heat to dissipate.Wait 15-20 minutes to see if the code clears once the system cools naturally.