Accessed None trying to read property - having trouble understanding how to reference correctly

I am trying to add camera shake to the player when they fall, depending on the height the camera shake would be more, or less intense.
I was planning in storing the Z velocity and then use it in the “Play World Camera Shake”.

But I started getting this error:
Blueprint Runtime Error: “Accessed None trying to read property Player Camera Shake Landed”. Blueprint: Player Function: Execute Ubergraph Player Graph: EventGraph Node: Custom Event Player Camera Shake Landed

I tried to debug and make the Blueprints as simple as possible to find the error, and after some time looking online, I’ve seen that this error appears because I’m not referencing the Player Camera Shake Landed.
The problem is that I can’t reference That blueprint (shown in the first image below), probably because I don’t have it in my scene (but since its just camera shake, I don’t need to have it in the scene?).

How can I fix this or maybe do it in a different way?

I am new to UE4 and don’t have the skills to do this yet.
Any help would be very appreciated.