This also applies to 404 Not Found Error

Encountered when the PlexAPI is unable to find an access URL for the client/player. By default the script will attempt to route requests through the Plex server using GDM, see https://support.plex.tv/articles/200430283-network

The script will attempt to fallback to direct IP connections in the event GDM fails though not all players support this fallback

Steps to troubleshoot

1. Ensure Enable local network discovery (GDM) is enabled in your Plex Server > Settings > Network options
2. Enabled "Advertise as Player" in your Plex Client settings
3. Ensure your server and client are on the same subnet and there are no firewalls between them
4. Refresh your Plex.tv token in the PlexAutoSkip config.ini from a fresh web session
5. Restart your Plex server
6. Log in and out of your Plex client
7. Review SSL Issues section

References: python-plexapi#644, #3

You should also check and make sure you client shows up on the client list and try all steps listed here https://support.plex.tv/articles/201812803-plex-companion-remote-control-issues/

Encountered when a player rejects an access request as unauthorized

Steps to troubleshoot

1. Turn on Advertise as player on your Plex client is offered (AndroidTV does not have this option)
2. Refresh your Plex.tv token in the PlexAutoSkip config.ini from a fresh web session
3. Restart your Plex server
4. Log in and out of your Plex client
5. Review SSL Issues section

SSL certificate issues can cause trouble especially when your Plex Server > Settings > Network > Secure Connections is set to Forced. If you are experiencing errors try changing this temporarily to Preferred for testing. You should also try configuring the script to connect to your server using Plex.tv instead of a manual IP address configuration if you aren't already. You can also try disabling certificate checks by setting ignore-certs in the [Security] section of your config.ini file to true.

Changing to Preferred and using ignore-certs = true are only meant for troubleshooting but can help identify underlying SSL issues but should not be used indefinitely as this reduces your networking security

Plex has recently removed the "advertise as player" feature from the Plex Web client as well as its desktop clients for Windows/Mac/Linux which breaks the PlexAutoSkip functionality. I'm unclear why this feature which has been stable and present for years was removed without warning, but the patch notes can be found here and here.

Currently I would recommend rolling back to Plex Desktop Client Plex-1.41.0.2876-e960c9ca or Plex Server Plex-1.27.2.5929-a806c5905 which still includes Plex Web 4.76.1. If you access the web player via plex.tv/web this will be a newer version of the web player which will not support "advertise as player", you'll need to access the web client from the local plex server address (localhost:32400/web).

You can disable the auto update feature of the Plex Desktop Client by accessing the plex.ini file in C:\Users\<username>\AppData\Local\Plex and adding the disableUpdater line to the debug section

[debug]
disableUpdater=true

This is a temporary solution unfortunately and I would encourage all of your who support this project and hope for similar projects in the future to voice your support on the Plex forums