Ai doesnt chase the player/ how to solve this runtime error?

I’m pretty newbie to this ai stuff and I’m trying to make the ai chase the player when it sees it but it gives me a run time error as soon as the even is fired.

In the Ai perception → sense, did you check all three for “Detection by Affiliation?”
You need to check all three to make AI sense other characters.
AI Perception | Unreal Engine Documentation

Hi, it says that your BlackBoardKey in your first image is None. It should be a reference to the blackboard. How do you set that?

The AI controller does have a Blackboard variable.

Also for AIs I only ever used AI perception inside the AI controller, never inside the pawn.