Tablo Channel - Some stations work, some don't

I have Tablo, and all channels work using the Tablo interface (web based specific to Tablo), but when using the Plex Channel for Tablo only some work. For example, 5.1 (NBC) works but when I try to launch 2.1 (Fox) I get "This channel is not responding" message. Again, this station works when using Tablo by itself. Tried rebooting, reloading etc.

BTW - I'm switching from HDHomerun to Tablo, hoping the interface is better.

Last question - is the experience any better using Roku3 vs. Xbox 360? I'm using Xbox, and am thinking about getting Roku.

Thanks!