PMS Transcoder not working while Server is on VPN

Plex Media Server Remote Access
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Server Version#: Windows Server 2012 R2
Player Version#: Web Player, Mobile App, Windows App.

Hello, I’ve been trying to get set up an AIO indexer and plex media server for a while, especially for out of country indexers only compatible with WAN IPs belonging to specific regions, and also remain anonymous. To do so the best way so far I’ve seen is to set up my networking with a VPN and all the requirements to accomplish traffic while hosting PMS. So far everything works fine, with the exception of the transcoder it seems.

While on VPN with Split Tunneling enabled, and ports forwarded, the media stream errors out with “Conversion failed. The transcoder exited due to an error.” while on the Web App and “An Error occurred while attempting to play this video. Please check your connection and try again” when using the non-server systems mobile/TV apps or Plex Media Player app on other windows devices.

The Media plays fine on the Web player and Media player on the local server using both the external dynamic DNS and port as well as the intranet localhost and port.

Browsing the media library, library scanning, reaching the media server from the internal network, and externally works fine, just the transcoding part seems to not work at all while the VPN is on.

I’ve also tried setting up static routes to plex.tv and plex.com IP addresses in case the transcoder or other function sends any traffic out there during playback, but this also doesn’t work. The VPN’s split tunnel allows internal network communications, and only the traffic from my browser and indexing services go through the VPN traffic.

Additionally, while on the VPN, I also cannot access the PMS settings under Settings, can access Dashboard, Alerts, Sync, and Conversions fine, but nothing below that like Remote Access settings, transcoder settings, etc. As soon as the VPN is disconnected everything works again 100%.

Is there some component of Plex that may need to be explicitly whitelisted, or can anyone help understand exactly how plex transcoder, or PMS in general handles the data being sent out to non-PMS clients?

I have the logs during playback sessions while on the VPN, along with any information to help diagnose.

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Can you share more information about this?

  • What VPN software and VPN provider are you using?

  • How have you configured split tunneling currently? That can mean a number of different things - you mention a few!

  • Do you mean VPN port forwarding, or local router port forwarding?

  • Does your DNS server change when you establish a VPN connection?

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Hey thank you so much for the reply:

  • What VPN software and VPN provider are you using?
    ExpressVPN
  • How have you configured split tunneling currently? That can mean a number of different things - you mention a few!
    Split Tunneling has been tried 3 different ways:
  1. split tunnel with all apps going through VPN.
  2. split tunnel with only selected apps NOT going through VPN. (apps not going are all .exe and services pertaining to Plex and others.
  3. split tunnel with only selected apps GOING through VPN. (apps selected to be indexers and such).
  • Do you mean VPN port forwarding, or local router port forwarding?
    local router port forwarding through dynamic dns.
  • Does your DNS server change when you establish a VPN connection?
    yes, changes to ExpressVPN DNS servers.
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Hi,

I am also have the same exact issue as you are with the same set up with ExpressVPN, the split tunnels and the port forwarding. I was able to get everything to work on the previous Plex version 1.20.5.3600 but once I updated to 1.21.0.3711, I get that transcoding error even though my remote access says “Fully accessible outside your network”. Not sure if it’s a Plex issue or an issue with ExpressVPN but I have not been able to figure it out. ::sigh::

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I have also noticed that playing back movie files that are MP4 are fine but I get the transcode error with files that are MKV. :thinking:

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Getting apps excluded from VPN is a real crap-shoot with different VPN provider apps.

I would ask if you excluded all of the Plex apps, but you said that you also did it the other way around, off-by-default and only including some apps.

So it sounds like just having the VPN active is enough to cause the problem.

That said, I’m not sure why that would cause a Transcoder problem.

Maybe it’s worth gathering & sharing server logs from when it happens.

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Definitely correct, I think it may be that the Plex transcoder somewhere relies on another component that we’re missing in the split tunnel. Or we need a static route to some other range of IPs outside of the plex.tv range that we’re not aware of.

For now my workaround is hosting a Hyper-V virtual machine as the downloader/indexer running the VPN client.

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Has anyone discovered the culprit to this issue? It is quite important to find a fix since VPN is nowadays an integral part of people’s daily work.

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No, sorry so far the workaround I’m using is to run a virtual machine in charge of the VPN and indexers/services, with split tunnel enabled. Then just running Plex Server on another machine. Without knowing how the transcoder works network-wise I guess we’ll never find out. Unless a Plex engineer actually chimes in.

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I think I finally found a solution- well this worked for me.

  1. So the VPN is not the main issue. You still want to whitelist Plex or use the split tunnel but you want to make sure your remote access has the green check mark before you turn your VPN on. Once you turn it on you will lose access to the server settings because Plex is whitelisted. So to gain access to server settings you need to un-whitelist it on your VPN.

  2. I was getting this transcoder issue on some movies and not others not because of the movie files (mp4 vs mkv etc.) but because some of the subtitle (SRT) files are either corrupted or can’t be transcoded when the VPN is on. I’ve watched these movies on my Admin account with the subtitles on and it keeps the subtitle on as default. The easiest way is to refresh all meta data to reset all the movies on your server to have subtitles off. I noticed this was only with SRT subtitle files and PGS were fine for whatever reason.

  3. Another option is when you’re streaming and get that transcoder error on your TV/smart device just turn the subtitle option to OFF and that should work as well.

Good luck! I hope it works for you guys.

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