In addition, if you use a remote URL in an ErrorDocument 401, the client will not know to prompt the user for a password since it will not receive the 401 status code.

Getting the VLsub VLC error code 401 Unauthorized 200 when searching or downloading subtitles, use the method in this post to fix the issue.

The 401 unauthorized status code usually means that the client request has not been completed due to a lack of valid authentication credentials designed for the requested resource.