cannot rewind or fast forward in YouTube

Try this for any misbehaving app:

• Force-quit the app, then relaunch and try again.
• If the issue persists, restart the device, then relaunch and try again.
• If the issue persists, delete the app, re-download and try again.
• If the issue still persists, then contact the app developer for further assistance.

Like all apps on Apple TV that follow the interface guidelines, the intended way to go to a different part of the content, is to pause and then move the ‘playhead’ on the timeline, then resume.

On what device and model is this happening?