Is the pan charge going off??
Try the flint bevel up then down, watch where the sparks are going in the pan "without a charge there mind you" make sure the sparks are going into where the prime is.
If with a new flint your not getting ignition of the primer in the pan, you may need your frizzen to be rehardened or replaced, or a new "stronger" main spring.
If you are getting prime ignitions yet its just flashing in the pan, you should then look at the barrel, is there oil or grease buggering up your charge, is the touch hole clear.
Flintlocks can be quite relyable, you just have to do your part! Sometimes pedersoli flintlocks need some work to make them 100%.
A few weeks ago I was at the infantry school and had great success with what was onece a most hated and troublesome pedersoli bess,
I replaced the lock springs and shaved the breech a bit she now makes fire 100%
I squeezed off many rounds in less then favourable conditions, running, crawling, marching and in the rain with ZERO misfires or flashes in the pan!!
I came very close to selling this bess a couple months ago...I am very very very glad now that I didnt.
What Im saying is dont give up, if you stick it out and solve whatever the problem is im sure you will be captivated by the majestic flintlock!!!!