Looks like a case sensitivity issue with APickup. You’ve defined it as APickUp in PickUp.h, but using APickup in in SpawnVolume.h/cpp. Change it to APickUp in SpawnVolume.h/cpp.
Looks like a case sensitivity issue with APickup. You’ve defined it as APickUp in PickUp.h, but using APickup in in SpawnVolume.h/cpp. Change it to APickUp in SpawnVolume.h/cpp.