A couple of questions!
Are all your wires,connectors (two or three) in good condition,
No cracks in wire insulation etc.
How often is maintance performed, when was last inapectuon?
Do you get spark in your burner during trial ignition period?
Do you get any flame at trial ignition period?
If yes, how big?
If flame is of sufficant size, check flame rod.
Last time flame rod cleaned, changed?
Pull flame rod! Is is smooth,free of oxidarion,pits in metal?
If it is not pitted,clean with light sanding of rod surface with 400 grit
Sand paper.
Still doesnt work or if rod hasnt been changed in a few
Years, then change rod.
If it still does not work,check flame signal strenght.
If good then is a gas problem! Call your tech,IF they have gas experiance,
It will be simple fix.
Good luck!
Winston
(904)3430848