Unable to package for HTML5

I am trying to package my project for deploying on HTML5. However, I am unable to do so.
Here is the error I am getting

INFO:root:(Emscripten: Running sanity checks)
2>  INFO:root:Closure compiler (E:\UE4\Epic Games\4.12\Engine\Source\ThirdParty\HTML5\emsdk\emscripten\1.35.0\third_party\closure-compiler\compiler.jar) does not exist, check the paths in E:\UE4\Epic Games\4.12\Engine\Intermediate\Build\HTML5\.emscripten
2>  INFO:root:closure compiler will not be available
2>EXEC : error : Linking globals named '_Z14UELinkerFixupsv': symbol multiply defined!
2>  Traceback (most recent call last):
2>    File "E:\UE4\Epic Games\4.12\Engine\Source\ThirdParty\HTML5\emsdk\emscripten\1.35.0\emcc", line 1309, in <module>
2>      final = shared.Building.llvm_opt(final, link_opts, DEFAULT_FINAL)
2>    File "E:\UE4\Epic Games\4.12\Engine\Source\ThirdParty\HTML5\emsdk\emscripten\1.35.0\tools\shared.py", line 1465, in llvm_opt
2>      assert os.path.exists(target), 'Failed to run llvm optimizations: ' + output
2>  AssertionError: Failed to run llvm optimizations:
2>ERROR : UBT error : Failed to produce item: D:\GitLab\YoApp\YoApp\Binaries\HTML5\YoApp-HTML5-DebugGame.js
2>  Total build time: 155.46 seconds
2>C:\Program Files (x86)\MSBuild\Microsoft.Cpp\v4.0\V140\Microsoft.MakeFile.Targets(42,5): error MSB3073: The command ""E:\UE4\Epic Games\4.12\Engine\Build\BatchFiles\Rebuild.bat" YoApp HTML5 DebugGame "D:\GitLab\YoApp\YoApp\YoApp.uproject" -waitmutex" exited with code -1.

I went to the path to look if the compiler.jar was present, I found out that it was not present. In fact the whole third_party folder under 1.35.0 was missing.

Can someone please guide me on how to proceed from here. Any help would be greatly appreciated.

Thanks!

Hi!

You have installed on your computer Microsoft C++ Visual Studio 2015? If not, download it and install on your computer.

You always need Visual Studio when you create packages for any platform.

I have already installed that.

I have a similar error when I package C++ project, or if I enable “Nativize Blueprint Assets” in the project settings in the BP project.

HTML5 is still an experimental feature and sometimes it doesn’t work correctly.

I didn’t enable the “Nativize Blueprint Assets” but still its giving the error.