slime spawner does not work, when placed there is no mob, and errors, I'm sure its just a missing space in code, current spawner is slimedisplayholographis

Sounds like a plugin conflict. I'll take a look at Holographic Displays and ping the author, if I'll find something.

Issue is caused by filoghost/HolographicDisplays#44, closing this since I am unable to change this.