Knoxhy 3004

Hi people. I've been trying to make a set-up involving the auto-spawner and grinder for a quick fix of Ender Pearls and ink and other assortments or goodies. The problem i'm having is that when I put a safari net in the spawner that contains an Enderman or squid (these are the ones I've tested and no go so far) it doesn't seem to work. I have made sure that it all runs properly with other mobs and is full of power and mob essence. Is there a way to rectify the issue or do I have to just simply go hunting???? ALSO. A friend of mine shares my map file on the same computer but they got Endermen out of the spawner... DAFAQ?!?!?! TIA