404 error when trying to access shared libraries

[SWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWMI]

The external player works when playing personal files fine. But when trying to play shared files from another computer (on the same network but on a different account), I get a 404 error:

Plex External Player Error calling: http://127.0.0.1:32400/library/metadata/34157?includeConcerts=1&includeExtras=1&includeOnDeck=1&includePopularLeaves=1&includePreferences=1&includeChapters=1&asyncCheckFiles=0&asyncRefreshAnalysis=0&asyncRefreshLocalMediaAgent=0. Response: 404 Not Found Code:404 Message: Not Found

I used to be able to play these shared files using an external player ~20 days ago.

Chrome's inspect console reports an error in background.js:formatted:1647 which would be this block:

}).always(function(a) { a.forEach(function(a) { a.aborted || (a.xhr = f(a.details, a.callbacks, a.internal ? { internal: !0 } : void 0)) }) });

Is there something wrong or is it on my end?