Why didn't the mozzarella cheese melt on my homemade pizza
I have personally had problems with low-fat, fat-free, etc cheese not melting. If you didn't use the good 'ol unhealthy stuff then that could be the issue.
How hot was your oven? It needs to be at approximately 425 degrees. Bake for 10-13 minutes.
If it's just a cheap pizza. I'm shure the cheese is low quality and full of fillers. Try switching brands. You are not alone!
The higher the FAT content in the mozzarella the better the melting quality. The low fat or skim milk cheeze doesn't do as well melting.
Try turning up the heat in your oven or putting the pizza in longer. Or maybe you just have too much cheese on it for it to melt.
If it was fresh motzarella that does not melt as well as the graded motzarella, you may want to try the graded kind next time.
At the last 3-5 minutes turn your oven onto high broil with the pizza on the lower rack appx. 6" away from the broiler and leave the oven door slightly cracked open, hope that helps.