Thanks for posting here in the Community.
Can you please provide us with more information regarding the issue you are experiencing? Does the issue only occur only in the YouTube channel or all channels on your Roku device?
We would recommend removing the channel from the Roku home screen by navigating to the channel tile, pressing the * key on your remote, and choosing 'Remove channel'. Then restart your device from Settings>System>System restart. Once your player starts up again, add the channel back once more.
To help troubleshoot the issue further, follow this link: How to resolve a channel playback issue
Please keep us posted and we'll continue assisting you from there.