If there is no spark at the pilot with a piezo igniter.
No spark at the pilot is an indication of a loose connection, a bad ground, or cracked ceramic around the electrode.
Check to ensure electrode wire is connected at the push button igniter (where applicable) and at the electrode. Loose connections can be tightened by gently squeezing the loose connection with small pliers. If the piezo is held in place by a nut, ensure the nut is tightened properly. A cracked ceramic igniter must be replaced.