How to make a FABRIK Effector follow a mesh

Hey,

So I have a robot with four arms and a lot of joints on each arm and I used FABRIK to solve the IK.
I am trying to make the effector/tip bone follow a mesh in the scene and have tried a lot of stuff but nothing seems to work. I’m pretty sure I’m missing something obvious here.

So when I’ve selected tip/root/effector in the Animation Blueprint and checked that it works in the preview I created a Poseable Mesh to be able to make the effector bone (named Arm3_13) follow a mesh around by using the “Set Bone Location” function.

This is what the blueprint looks like:

https://imgur.com/a/XcMON

However when I do that, this happens:

https://i.imgur.com/iwadgPH.png

The bone stretches and the rest of the bone chain doesn’t move at all even though I change the effectors location in the scene.

This is what it looks like in preview and what I’d like in the scene:

https://imgur.com/4yAu6Tr

I’m still learning UE4, so again, it’s probably something obvious, but I havnt been able to find a fix for it.