Access violation - code c0000005 (first/second chance not available)

UE4Editor_UnrealSandboxTerrain!std::_Func_impl_no_alloc<<lambda_6de920837b5fa348de01dfd582cbde75>,void>::_Do_call() [c:\program files (x86)\microsoft visual studio\2017\community\vc\tools\msvc\14.16.27023\include\functional:16707566]
UE4Editor_UnrealSandboxTerrain!ASandboxTerrainController::Tick() [c:\users\admin\desktop\ue4voxelterrain\ue4voxelterrain\plugins\unrealsandboxterrain\source\unrealsandboxterrain\private\sandboxterraincontroller.cpp:178]
UE4Editor_Engine!AActor::TickActor() [d:\build\++ue4\sync\engine\source\runtime\engine\private\actor.cpp:914]
UE4Editor_Engine!FActorTickFunction::ExecuteTick() [d:\build\++ue4\sync\engine\source\runtime\engine\private\actor.cpp:137]
UE4Editor_Engine!TGraphTask<FTickFunctionTask>::ExecuteTask() [d:\build\++ue4\sync\engine\source\runtime\core\public\async\taskgraphinterfaces.h:829]
UE4Editor_Core!FNamedTaskThread::ProcessTasksNamedThread() [d:\build\++ue4\sync\engine\source\runtime\core\private\async\taskgraph.cpp:679]
UE4Editor_Core!FNamedTaskThread::ProcessTasksUntilQuit() [d:\build\++ue4\sync\engine\source\runtime\core\private\async\taskgraph.cpp:575]
UE4Editor_Core!FTaskGraphImplementation::WaitUntilTasksComplete() [d:\build\++ue4\sync\engine\source\runtime\core\private\async\taskgraph.cpp:1444]
UE4Editor_Engine!FTickTaskSequencer::ReleaseTickGroup() [d:\build\++ue4\sync\engine\source\runtime\engine\private\ticktaskmanager.cpp:556]
UE4Editor_Engine!FTickTaskManager::RunTickGroup() [d:\build\++ue4\sync\engine\source\runtime\engine\private\ticktaskmanager.cpp:1474]
UE4Editor_Engine!UWorld::RunTickGroup() [d:\build\++ue4\sync\engine\source\runtime\engine\private\leveltick.cpp:783]
UE4Editor_Engine!UWorld::Tick() [d:\build\++ue4\sync\engine\source\runtime\engine\private\leveltick.cpp:1460]
UE4Editor_UnrealEd!UEditorEngine::Tick() [d:\build\++ue4\sync\engine\source\editor\unrealed\private\editorengine.cpp:1726]
UE4Editor_UnrealEd!UUnrealEdEngine::Tick() [d:\build\++ue4\sync\engine\source\editor\unrealed\private\unrealedengine.cpp:403]
UE4Editor!FEngineLoop::Tick() [d:\build\++ue4\sync\engine\source\runtime\launch\private\launchengineloop.cpp:3699]
UE4Editor!GuardedMain() [d:\build\++ue4\sync\engine\source\runtime\launch\private\launch.cpp:174]
UE4Editor!GuardedMainWrapper() [d:\build\++ue4\sync\engine\source\runtime\launch\private\windows\launchwindows.cpp:145]
UE4Editor!WinMain() [d:\build\++ue4\sync\engine\source\runtime\launch\private\windows\launchwindows.cpp:276]
UE4Editor!__scrt_common_main_seh() [f:\dd\vctools\crt\vcstartup\src\startup\exe_common.inl:283]
kernel32
ntdll