After enabling pixel streaming, when running your Unreal game in your local development environment, you may experience crashes if you haven't included the PixelStreamingPort and PixelStreamingIP flags at the command line.
This is because the endpoints that the pixel streaming plugin is looking for do not exist and are null...thus causing the game to crash.
Include the PixelStreamingPort and PixelStreamingIP flags as shown below:
game.exe -PixelStreamingPort=8888 -PixelStreamingIP=127.0.0.1