When I run the script and enter the trigger box, print string does not output the Hello command, I output the number of elements separately, there are 5 of them Begin Object Class=/Script/BlueprintGraph.K2Node_ActorBoundEvent Name="K2Node_ActorBoundEvent_6" DelegatePropertyName="OnActorBeginOverlap" DelegateOwnerClass=Class'"/Script/Engine.Actor"' EventOwner=TriggerBox'"/Game/ThirdPersonBP/Maps/ThirdPers posted by anonymous | blueprintUE | PasteBin For Unreal Engine
are you sure the objects in the scene are of the type you are selecting?
can you put in some more Print strings:
-immediately after the BeginOverlap() including that OtherActor->Name (you might not actually be registering the overlap in the first place)
-after the GetAllActorsOfClass() maybe outputting the array length (the GetAllActorOfClass() might not be able to find anything that matches you class)