I recommend that you post in this thread: Error Code: s3015 (Media) and when you do, include the following information:
Plex Server version and OS
Plex client (which app) and version (is this on a web browser? or other app?)
and following the instructions in that thread for posting logs:
https://support.plex.tv/articles/201643703-reporting-issues-with-plex-media-server/
https://support.plex.tv/articles/200250417-plex-media-server-log-files/
And depending on the plex app you’re using, you may need to post a log from that as well…
