I am having a similar issue. I open the game, start with my friend and after from what varies to a few seconds to a few minutes my game crashes with an error that sounds like yours.
LowLevelFatalError [File:D:\BuildAgent\work\40b40aa365e0f6fc\Haze1\Main\Engine\Source\Runtime\RenderCore\Private\RenderingThread.cpp] [Line: 815] Rendering thread exception: LowLevelFatalError [File:D:\BuildAgent\work\40b40aa365e0f6fc\Haze1\Main\Engine\Source\Runtime\Windows\D3D11RHI\Private\D3D11Util.cpp] [Line: 182] Unreal Engine is exiting due to D3D device being lost. (Error: 0x887A0006 - 'HUNG')
