On both the phone (where i’m trying to remote control), and the desktop (where playback is happening on web), accessing :32400/clients shows me the below. On an iPad with Chrome - the same url shows a blank page.
This XML file does not appear to have any style information associated with it. The document tree is shown below.
<MediaContainer size="0"> </MediaContainer>
Plex recently removed the capability of Plex Web and Plex Desktop to be controlled as a companion player. The suggestion is to use Plex HTPC instead (download, docs).