Thanks for reaching out here in the Community.
Do you receive an error code or message when accessing the channels?
If you haven't tried yet, you can try removing one of the affected channels then re-install it. To ensure the process is successful, make sure to restart your device before adding the channel back in. We would recommend doing this from the Settings menu by navigating to Settings > System > System restart > Restart.
For detailed instructions, refer to this Support link: How do I resolve channel playback issues?
Please keep us posted!
All the best,
Roku Forum Moderator