Firebird S 90 oil boiler tries to ignite but doesn't, Any Ideas??

I have a Firebird S 90 oil boiler that tries to ignite but doesn't. I can see the fire flash for and instant but does not catch. It will try around three times and then turn itself off. I hit the reset button and it tries around three more times and then shuts itself off. I have bleed it, plenty of oil in the tank and never been run dry, and it was serviced six months ago. No other issues leading up to this. Just started out of the blue.