TiVo

I'm using my own TiVo system along with a tuning adapter that I received from Cox. We had a hard time getting it connected initially, but after a while it worked great. now I am getting this message on some channels (Fox News, Fox Business, USA, etc):

this channel is not authorized. Contact your cable advisor for more information (V58)

The channels will initially show up when we turn to theme, but after a few minutes the channel will go black and the above message will appear. any suggestions?