Without knowing anything about the pizza I can only take an educated S.W.A.G.
8-minute baking time at 250C is plenty of baking for most pizzas unless you are using the dough right out of the cooler, in that case it might not be.The color of the baking platform also comes into play here, is it dark, bright, seasoned, or not seasoned?
Remember, when troubleshooting pizza problems T.M.I. (too much information) is never a problem.
Tom Lehmann/The Dough Doctor