What type “Ability2 input” is? You sure it’s compatible? You sure it is not None? You can check what object is coming in by placing breakpoint on the node (right click and oyu will have option for that) and when breakpoint is triggered you can hover over pins to see what is inputed in to the pins, you caa verify if everything works as you expect
On the new blueprint you created, click on Class Settings, and verify if it really has a parent. If it does, the only explanation is that your object is having a null or invalid pointer. To check this, use the Is Valid node before you cast the object.
if it fails it means you casting to unrelated class, again use breakpoint on cast to see what type of object cast node in getting, then you can class tree to see if class you casting to is related to class of the object that cast ndoe is getting, you can use Class Viewer (Window->Devlopment Tools->Class Viewer). You can also cast only to the for most class that object is, so if you got classes related like this A->B->C->D and you got object of class C in cast and link of class A, you can only cast it to class B or C not D.