Xfinity app error code TV APP-00231

Starting today, when I use the Xfinity beta app on either of my two smart TVs, I get an error code "TV APP-00231" but only on certain channels in the Xfinity channel lineup.  For example, when I try to access channels like MSNBC, CNN or Fox News, I get the error, but I can access various other channels like CBS, NBC and ABC.  I would appreciate any suggestions on how to fix this error.  Thanks.