Server Version#: 1.14.1.5488
Player Version#: 3.79.0
So I recently set up a new linux plex server on my local network with remote access via a custom domain/certificate.
Remote access to the server over the web app via app.plex.tv as well as my custom domain work fine as intended, but the problem is that when running the web app over my local network, my server comes up as ‘Remote’ via both app.plex.tv, and my custom domain (which resolves to the local ip of my server on my local network). I investigated the issue, and noticed CORS issues when looking at the console when loading the web app in Firefox (see below)
[Connections] Testing connection for plex-main at https://192-168-1-6.1cbca74bfda64b079f0710e76c1394a3.plex.direct:32400/media/providers main-1-351e2d6b7e8a3432e11b-plex-3.79.0-9783680.js:3615:161
[Connections] plex-main is unavailable at https://192-168-1-6.1cbca74bfda64b079f0710e76c1394a3.plex.direct:32400/media/providers (Status 0) main-1-351e2d6b7e8a3432e11b-plex-3.79.0-9783680.js:3615:161
[Connections] Prevented fallback to insecure connection for plex-main main-1-351e2d6b7e8a3432e11b-plex-3.79.0-9783680.js:3615:161
Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at https://192-168-1-6.1cbca74bfda64b079f0710e76c1394a3.plex.direct:32400/media/providers?X-Plex-Product=Plex%20Web&X-Plex-Version=3.79.0&X-Plex-Client-Identifier=x4rh94bt24dqpc6wapsheqhi&X-Plex-Platform=Firefox&X-Plex-Platform-Version=60.0&X-Plex-Sync-Version=2&X-Plex-Device=Linux&X-Plex-Device-Name=Firefox&X-Plex-Device-Screen-Resolution=2560x290%2C2560x290&X-Plex-Token=[REDACTED]&X-Plex-Language=en. (Reason: CORS request did not succeed).
This isn’t a DNS issue because it works in Chromium and Apps, but not in Firefox on the same computer, with the same network config, plus I already have DNS rebinding allowed for plex.direct on my LAN. You can even see the cURL request work correctly with the same domain, so there’s basically no way it’s a DNS issue.
Even if I completely avoid my local DNS resolver by using /etc/hosts for the relevant plex.direct domains, it still results in the same issue. Not being able to connect is definitely a CORS issue, please refer to the logs in my original post, with the most important line being this one:
Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at https://192-168-1-6.1cbca74bfda64b079f0710e76c1394a3.plex.direct:32400/media/providers?X-Plex-Product=Plex%20Web&X-Plex-Version=3.79.0&X-Plex-Client-Identifier=x4rh94bt24dqpc6wapsheqhi&X-Plex-Platform=Firefox&X-Plex-Platform-Version=60.0&X-Plex-Sync-Version=2&X-Plex-Device=Linux&X-Plex-Device-Name=Firefox&X-Plex-Device-Screen-Resolution=2560x290%2C2560x290&X-Plex-Token=[REDACTED]&X-Plex-Language=en. (Reason: CORS request did not succeed).
The browser is literally saying that it will refuse to connect due to CORS. At this point, the browser will not have even attempted to resolve the DNS for this domain yet since it was caught in the browser’s security check for a cross origin resource sharing fetch.
The problem was an extension called privacy badger.
After looking into this further, I discovered that I had the privacy badger extension which prevented this from working properly. Unfortunately with the logs in the console citing CORS, this was not obvious…
Regardless, adjusting the settings in privacy badger allowed me to regain my local connection with the web app, so this is not a bug.
This issue is resolved. I’ve edited my posts to have more useful/relevant information so hopefully anyone with this problem in the future can find this thread.
