Your boiler has repeatedly failed to keep its flame lit, so it has safely shut itself down to prevent any issues.

Flame loss detected five times in 24 hours GAS SUPPLY Check the gas supply pressure Check the gas valve calibration ELECTRODE PROBLEM Check the electrode connection and wiring Check the condition of the electrode FLUE GAS PIPES Check the air intake and flue gas exhaust pipes EXCHANGER ON FLUE GAS SIDE BLOCKED Check the cleanliness of the exchanger MAINS VOLTAGE Check the power supply voltage