iPhone won't play Plex video

[sa2000]

@SilentWatcher

I’ve using Plex on AppleTV and all my content is stored on an old iMac running on Lion.

I know Plex made changes that a few months that made my iMac an outdated server but I was aware until I uninstalled the tvOS app recently will trying to fix a separate issue. I haven’t got the hard rive space on my newer MacBook to hold my Plex library but I was then able to stream the Plex library from my iPhone 4 to AppleTV with Airplay.

However, a few days ago my iPhone stopped being able to Plex content. Every video, regardless of format gives this message - The operation could not be completed An unknown error occurred ( -12880 ).

I have tried restarting the browsers and apps on the iMac and iPhone and restarting the devices themselves.

Is this error connected to the reason why the iMac doesn’t work with AppleTV anymore?

Can anyone give me a solution?

Regards

Old versions of the server e.g. 0.9.16.6.1993-5089475 are no longer supported by the Plex for iOS and Plex for tvOS apps for iPhone/iPad and Apple TV

Advance warning was given here for Plex for iOS

Plex for iOS

Note: In an upcoming release, the minimum supported version of Plex Media Server will be increased to 1.3.0. Please upgrade your servers.

and the change made in version 4.28 for Plex for iOS
See Plex for iOS - #78 by sergiou87

and here for Plex for Apple TV

Plex for Apple TV

Note: In an upcoming release, the minimum supported version of Plex Media Server will be increased to 1.3.0. Please upgrade your servers.

and the change made in version 1.27 for Plex for Apple TV
See Plex for Apple TV - #44 by sergiou87