For some reason I am unable to spawn any Nether Mobs using the /SpawnMobs command or even /Summon command in the regular world (not nether or end). The only thing I am able to spawn using /SpawnMobs is the Wither. Other than that I can't spawn any of the alternatives. Now if I try to spawn a regular world mob I can. But other than that I am unable to. If need be I will get a list of plugins and list them here. But I looked through them all and nothing seems to be blocking spawning of those specific mobs.