Hi @Alexac314,
Thank you for your first post here in the Roku Community!
We appreciate the troubleshooting steps that you have done so far. If the issue persists on one channel after attempting the troubleshooting steps and videos from other channels play fine, contact the channel provider's customer support team to report the problem and get help. The channel developers themselves maintain channels on Roku. In this case, an issue within that specific channel likely needs to be addressed with an update from them.
If there's anything else that we can do to assist you, please keep us posted.
Kind regards,
John
John
Roku Community Moderator