Crash problem c++

my editor crash with this issue.

UE4Editor_RevealGamesLightFall_4370!AC_Weapon::AttachMeshToPawn() [f:\graphics engine\unreal engine 4\epic games\gameproject\ProjectName\source\ProjectName\c_weapon.cpp:96].

the problem is,

if(MyPawn) <— Problem (Line:96)

{

Code

}

Reference to my pawn.

UPROPERTY(Transient, Replicated)

class AC_FPCharacter* MyPawn;

I don’t know why it crash.