Thanks for reaching out here in the Community.
Does the same issue occur when you access a different content within Paramount Plus?
If you haven't tried yet, you can remove the affected channel and 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 > Power (If you do not see a Power submenu, skip to the next step.) > System restart.
For detailed instructions, refer to this Support link: How do I resolve channel playback issues?
Keep us posted!
All the best,
Roku Forum Moderator