Failed to link patch

[Vaan]

I try to create an inventory for an Escape Room game following this tutorial: UNREAL INVENTORY STEP BY STEP || Unreal Engine Tutorial - YouTube

In my Item.h i have this code:

// Fill out your copyright notice in the Description page of Project Settings.

#pragma once

#include "CoreMinimal.h"
#include "GameFramework/Actor.h"
#include "Components/StaticMeshComponent.h"
#include "Item.generated.h"

UCLASS()
class VIATADESTUDENT_API AItem : public AActor
{
	GENERATED_BODY()
	
public:	
	// Sets default values for this actor's properties
	AItem();

protected:
	// Called when the game starts or when spawned
	virtual void BeginPlay() override;

	bool isVisible;

public:	
	// Called every frame
	virtual void Tick(float DeltaTime) override;

	FORCEINLINE class UStaticMeshComponent* GetMesh() const { return itemMesh; }

	UFUNCTION(BlueprintPure, Category = "Item")
		bool GetActive();

	UFUNCTION(BlueprintCallable, Category = "Item")
		void SetActive(bool visible);

	UFUNCTION(BlueprintCallable)
		void Touched();

	UPROPERTY(EditDefaultsOnly)
		FString name;

	UPROPERTY(EditDefaultsOnly)
		FName itemID;

private:
	UPROPERTY(VisibleAnywhere, Category = "Item")
		class UStaticMeshComponent* itemMesh;
};

And in my Item.cpp i have this:

// Fill out your copyright notice in the Description page of Project Settings.


#include "Item.h"

// Sets default values
AItem::AItem()
{
 	// Set this actor to call Tick() every frame.  You can turn this off to improve performance if you don't need it.
	PrimaryActorTick.bCanEverTick = true;

	isVisible = true;

	itemMesh = CreateDefaultSubobject<UStaticMeshComponent>(TEXT("itemMesh"));
	RootComponent = itemMesh;

	GetMesh()->SetSimulatePhysics(true);

	name = "null";
	itemID = FName("null");
}

// Called when the game starts or when spawned
void AItem::BeginPlay()
{
	Super::BeginPlay();
	
}

// Called every frame
void AItem::Tick(float DeltaTime)
{
	Super::Tick(DeltaTime);

}

bool AItem::GetActive()
{
	return isVisible;
}

void AItem::SetActive(bool visible)
{
	isVisible = visible;
}

void AItem::Touched()
{
	this->SetActive(false);
	this->SetActorHiddenInGame(true);
}

This is the error:

Item.gen.cpp.obj : error LNK2019: unresolved external symbol "public: void __cdecl AItem::SetActive(bool)" (?SetActive@AItem@@QEAAX_N@Z) referenced in function "public: static void __cdecl AItem::execSetActive(class UObject *,struct FFrame &,void * const)" (?execSetActive@AItem@@SAXPEAVUObject@@AEAUFFrame@@QEAX@Z)
Item.gen.cpp.obj : error LNK2019: unresolved external symbol "public: void __cdecl AItem::Touched(void)" (?Touched@AItem@@QEAAXXZ) referenced in function "public: static void __cdecl AItem::execTouched(class UObject *,struct FFrame &,void * const)" (?execTouched@AItem@@SAXPEAVUObject@@AEAUFFrame@@QEAX@Z)
D:\Unreal Engine Projects\Viata de Student\ViataDeStudent\Binaries\Win64\UnrealEditor-ViataDeStudent.patch_3.exe : fatal error LNK1120: 2 unresolved externals
Failed to link patch (0.000s) (Exit code: 0x460)
---------- Finished (0.000s) ----------

Please help me

[DanM]

Try deleting your binaries and intermediate folders and rebuilding.