overheat safety trip

The red light was fast flashing. I turned off heating and hot water to let things cool down and then pressed the reset but it would not reset. I have turned off power to the boilermate and then after a few minutes turned back on but the flashing red came on again. I don't know what to do especially now with the cvirus, not good for engineer to be here. Self isolating as over 70 and husband previous health probs.