My FTB launcher through twitch will not launch minecraft

I have been playing minecraft through ftb launcher for quite some time now. I got the new twitch app and was able to continue playing. But just recently it abruptly stopped working. I sign into twitch and go to minecraft and try and launch, but it doesn't load like it used to. and when I hit the launch minecraft botton, it gives me this weird error code. "The version you are trying to play inherits properties from an unknown version". I have tried several things with no luck.