HTML5 crashing

One day I cooked for html5 without any problems, next day I can’t.
Please help.

LOG:

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

Fatal error: [File:D:\BuildFarm\buildmachine_++depot+UE4-Releases+4.7\Engine\Source\Runtime\Engine\Private\Materials\MaterialShared.cpp] [Line: 1331]
Failed to compile default material DefaultLightFunctionMaterial!

KERNELBASE + 37901 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_Engine!FMaterial::CacheShaders() + 1222 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\engine\private\materials\materialshared.cpp:1331]
UE4Editor_Engine!FMaterial::CacheShaders() + 102 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\engine\private\materials\materialshared.cpp:1227]
UE4Editor_Engine!UMaterial::CacheShadersForResources() + 261 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\engine\private\materials\material.cpp:1520]
UE4Editor_Engine!UMaterial::CacheResourceShadersForCooking() + 743 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\engine\private\materials\material.cpp:1505]
UE4Editor_Engine!UMaterial::BeginCacheForCookedPlatformData() + 399 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\engine\private\materials\material.cpp:2094]
UE4Editor_UnrealEd!UCookOnTheFlyServer::TickCookOnTheSide() + 3104 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\editor\unrealed\private\cookontheflyserver.cpp:1125]
UE4Editor_UnrealEd!UCookOnTheFlyServer::Tick() + 41 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\editor\unrealed\private\cookontheflyserver.cpp:430]
UE4Editor_UnrealEd!FTickableEditorObject::TickObjects() + 164 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\editor\unrealed\public\tickableeditorobject.h:15]
UE4Editor_UnrealEd!UEditorEngine::Tick() + 1635 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\editor\unrealed\private\editor.cpp:1110]
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]

Verifying Unreal Engine in Epic Games Launcher solved this problem.