I play in an 1-8 person server on mobs are spawning. The game is on normal, there are no cheats on, and there are no world prefrences on. There are still peaceful mobs spawning such as sheep, and cows, and there are still mobs spawning in the end and nether. I dont know why any hostile mobs wont spawn but it messes up our game in getting experiance, and trying to play minecraft. Thank you for reading this!