If your viewers are unable to view a shared video link due to the error message, “Unauthorized: You are unauthorized for this action”, this is likely due to the privacy setting of the shared video.
You can troubleshoot this by changing the privacy setting of the video. Refer to the Overview of video privacy settings article for more information.
If you are an Enterprise member, make sure that the recipient has access to the folder in which the video is stored. Refer to How to share a video with your team.