I am New to unreal Engine and there is probably a simple fix but please can someone help?

![When making a blueprint to spawn enemies in a wave-like system I am running into an issue.
The First batch of enemies spawn but after that, the second batch of enemies doesn’t, This is the error I am getting.
Blueprint Runtime Error: Accessed None trying to read property CallFunc_Array_Get_Item1 from function: ‘ExecuteUbergraph_Interaction_GameMode’ from node: SpawnActor Enemy Character Pawn in graph: EventGraph in object: Interaction_GameMode with description.
Attached below is my blueprint and if someone could help it would be much appreciated.]

show how you are setting the array and/or adding items to it.