Graph is linked to external private object when using custom class

I created a custom C++ class actor and using a class reference for it in my Player BP. Everything is fine until I create the variable to hold the class. Then when i want to save it it says

Can’t save
Graph is linked to private object(s)
in an external package. External
Object(s): /Engine/Transient Try to
find the chain of references to that
object (may take some time)?

The code for my custom class header file:

#pragma once

#include "GameFramework/Actor.h"
#include "SmallShipClass.generated.h"

class PROJECT_API ASmallShipClass : public AActor
	// Sets default values for this actor's properties

	// Called when the game starts or when spawned
	virtual void BeginPlay() override;
	// Called every frame
	virtual void Tick( float DeltaSeconds ) override;

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Ship Data")
	FString Name;

Isnt Name already declared for all Objects?

Ok i found out, that it isnt that class which causes the problem. It is a non-public BPFuctionslibrary