Server Version#: 4.53.0
Player Version#: 11.2.6
When attempting to play via Sonos on any given speaker, I get the following message for Plex only: “The connection to Plex was lost.”
Everything else seems to work just fine. Remote content streaming and downloading, login via browser from home, browsing content also goes just fine on Sonos.
Evidently this issue arises and might have something to do with the ssl handshake or so I’ve heard (the connection gets dropped).
My server runs with a letsencrypt docker container providing ssl certs for my various sub domains, but I’m fairly confident Sonos works through plex apis tied to app.plex.tv anyway.
This has also been working flawlessly for at least 5 years so not sure what changed recently. 
