can not stream on demand content

I am using a Chromebook trying to stream on-demand content and I keep getting this message "  get your Adobe Flash Player up and running." I did make sure the flash player is not blocked.  it just does not pick up on that.   this only happens with on-demand content if I try streaming live tv there is no problem.  I already tried clearing all the cookies it did not help. I reset all the settings for the site and turned the computer off and back on. now it will not load the website at all ! it just stays on Xfinity .... page you see when it first loads. when I go in incognito mode I am able to stream live tv but not on-demand content. please have ideas help me, please