Plex integration - Client is not currently accepting playback controls

[summer ocean]

I'm trying various things to get home assistant to play something on plex. Via the Plex integration on HA, I can see my activity on plex but if I try to launch an action or even change the media via the integration UI itself, I get the following error :
Failed to perform the action media_player/play_media. Client is not currently accepting playback controls: Plex (user - Plex for Roku - [etc.])
This is running on the Roku tv App for plex.
I have done a fresh restart of both the app and the TV as from my own research, that seems to be something that fixes the issue sometimes but in this case, no such luck.

Any advice on how to fix this? Thanks!

[summer ocean]

Installed Plex for HTPC and this is also the case on that. I'm incapable of using the Plex integration to control plex at all 🙁

[summer ocean]

I'm wondering if the main issue is that the Plex doesn't live on my network and so the integration can't get a secure connection to it and so it falls into a read-only mode