OnActorBeginOverlap in C++

Ok I re-created the blueprints and its behavior is as I expected to be. Anyway, I added OnActorBeginOverlap.AddDynamic(this, &AHealth::OnPickup); in the constructor and

void AHealth::OnPickup(AActor* OtherActor, UPrimitiveComponent* OtherComp, int32 OtherBodyIndex, bool bFromSweep, const FHitResult& SweepResult)
{
	GEngine->AddOnScreenDebugMessage(-1, 5.f, FColor::Red, FString::Printf(TEXT("on actor begin overlap works!")));
}

In the function OnPickup().

Now, I get 2 errors:

Unreal Engine:

Visual Studio: