The Spawn Block Isn't Spawning My Geckolib Entity

I'm making a horror mod currently and I'm almost done making it but there is just one problem that I don't know how to fix. The problem is that the spawn block isn't spawning my entity I'll send images of the spawning tab and the procedure to spawn it in. 

https://imgur.com/a/KX8DX3A 

https://imgur.com/a/NIPQA8b 

The entity is only meant to spawn on grass and to spawn a maximum of 50 blocks away from the player. 

Since I am a beginner please provide an image if possible.