Your boiler has too much water in the system, which puts extra stress on the internal components and may cause it to stop working for safety.

DIY fix possible

Check that the internal or external filling loop valves are fully closed.Locate a radiator bleed valve and use a key to release water into a container to lower the pressure.Monitor the pressure gauge until it returns to between 1.0 and 1.5 bar.Reset the boiler once the pressure has been reduced.