crash in spawning decal and emmiter in multiplayer

i want to spawn impact and decal in multyplayer in the projectile BP i made an event replecated as multicast and when i spawn the projectile every think good but when it try to spawn the decal and impact it crash the project and this is the report :: MachineId:850E439944718D37EA0E65B875FBD8E0
EpicAccountId:d11396c8451c47ac926af9533abef070

Unknown exception - code 00000001 (first/second chance not available)

Fatal error: [File:D:\BuildFarm\buildmachine_++depot+UE4-Releases+4.7\Engine\Source\Runtime\CoreUObject\Private\UObject\ScriptCore.cpp] [Line: 789]
Failed to find function None in MyProjectilemomo_C //Game//Maps//UEDPIE_2_AdvLaserDecals.AdvLaserDe

KERNELBASE + 35740 bytes
UE4Editor_Core!FOutputDeviceWindowsError::Serialize() + 292 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\core\private\windows\windowsplatformoutputdevices.cpp:95]
UE4Editor_Core!FMsg::Logf__VA() + 463 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\core\private\misc\outputdevice.cpp:526]
UE4Editor_CoreUObject!UObject::FindFunctionChecked() + 249 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:789]
UE4Editor_Engine!FRepLayout::CallRepNotifies() + 185 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\engine\private\replayout.cpp:1535]
UE4Editor_Engine!FObjectReplicator::PostReceivedBunch() + 838 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\engine\private\datareplication.cpp:749]
UE4Editor_Engine!UActorChannel::ProcessBunch() + 1950 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\engine\private\datachannel.cpp:1901]
UE4Editor_Engine!UActorChannel::ReceivedBunch() + 939 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\engine\private\datachannel.cpp:1787]
UE4Editor_Engine!UChannel::ReceivedSequencedBunch() + 31 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\engine\private\datachannel.cpp:262]
UE4Editor_Engine!UChannel::ReceivedNextBunch() + 2851 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\engine\private\datachannel.cpp:588]
UE4Editor_Engine!UChannel::ReceivedRawBunch() + 675 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\engine\private\datachannel.cpp:344]
UE4Editor_Engine!UNetConnection::ReceivedPacket() + 3880 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\engine\private\netconnection.cpp:979]
UE4Editor_Engine!UNetConnection::ReceivedRawPacket() + 266 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\engine\private\netconnection.cpp:457]
UE4Editor_OnlineSubsystemUtils!UIpNetDriver::TickDispatch() + 1367 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\online\onlinesubsystemutils\private\ipnetdriver.cpp:174]
UE4Editor_Engine!TBaseUObjectMethodDelegateInstance<0,UNetDriver,void cdecl(float)>::ExecuteIfSafe() + 231 bytes [d:\buildfarm\buildmachine++depot+ue4-releases+4.7\engine\source\runtime\core\public\delegates\delegateinstancesimpl_variadics.inl:772]
UE4Editor_Engine!TBaseMulticastDelegate::Broadcast() + 165 bytes [d:\buildfarm\buildmachine
++depot+ue4-releases+4.7\engine\source\runtime\core\public\delegates\delegatesignatureimpl_variadics.inl:1030]
UE4Editor_Engine!UWorld::Tick() + 1024 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\engine\private\leveltick.cpp:1027]
UE4Editor_UnrealEd!UEditorEngine::Tick() + 5618 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\editor\unrealed\private\editor.cpp:1329]
UE4Editor_UnrealEd!UUnrealEdEngine::Tick() + 22 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\editor\unrealed\private\unrealedengine.cpp:347]
UE4Editor!FEngineLoop::Tick() + 4179 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\launch\private\launchengineloop.cpp:2257]
UE4Editor!GuardedMain() + 1404 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\launch\private\launch.cpp:142]
UE4Editor!GuardedMainWrapper() + 26 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\launch\private\windows\launchwindows.cpp:126]
UE4Editor!WinMain() + 249 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\launch\private\windows\launchwindows.cpp:202]
UE4Editor!__tmainCRTStartup() + 329 bytes [f:\dd\vctools\crt\crtw32\dllstuff\crtexe.c:618]
… i cant deug becouse it crash every time