Hi @krbr,
Welcome to the Roku Community.
We'd like to look into this further. To clarify, have you tried to remove the channel and see if it helps? If you haven't tried it yet, you can remove the affected channel and re-install it. To ensure the process is successful, 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?
If you are still unable to play videos from one channel after attempting the suggestions above, videos from other channels play fine, contact the channel provider's customer support team to report the issue and get help. Channels on Roku are maintained by the channel developer themselves. In this case, there's likely an issue within that specific channel that needs to be addressed with an update from the channel developer.
Please let us know if there is anything else we can assist you with.
Regards,
Nimfa