On our server, hostile mobs will just not spawn, whether that be by /summon, spawn egg, spawner, or naturally. Passive mobs all seem to spawn. I have /gamerule DoMobSpawning as true, monster spawning set to on, difficulty set to normal, and have only installed the BetterSleeping and MoreMobHeads plugins and have deleted everything about them from the files yet hostile mobs still wont spawn.
Any ideas on how to fix it?