Gas boiler cuts out after being switched on

When I switch on our gas boiler (mynute he), it turns off after approximately 2 seconds. Link to newer model here https://www.vokera.ie/homeowners/boilers/mynute-vhe-2/

I checked a radiator to see if air would come out and there doesn’t seem to be an excess of air. The water pressure is at 2 bar so no problem there.

This started after a local power outage where the boiler was unpowered for several hours.

Any ideas?