Missing UE4Game binary

I am trying to add a streaming video to a widget and i can only get the sound without video,when i add the plugin web browser i get this error:

     PackagingResults:Error: Error Launch failed! Missing UE4Game binary.
     You may have to build the UE4 project with your IDE. Alternatively, build using UnrealBuildTool with the commandline:
     UE4Game <Platform> <Configuration>

Unreal engine 4.15 and the same in 4.16

I just package my app first and now its working.