Your boiler's internal water pressure is currently too high, which may cause it to stop working to protect the system from potential leaks or damage.

DIY fix possible

Turn off the boiler and let it cool down completely.Locate a radiator in your home that is easily accessible.Place a small container and cloth under the radiator bleed valve.Use a radiator key to open the valve slightly and release a small amount of water until the boiler's pressure gauge drops into the green zone (usually 1.0 to 1.5 bar).Close the valve tightly and check your boiler display to see if the error has cleared.