I am having the same problem. Once I initiate a stream to the PlexAmp headless, the PlexAmp controller (on an android phone) no longer reacts to play or pause.
This <> to coincide with the 4.3 upgrade, as prior it worked flawlessly.
I hope this bit of info helps:
I have PlexAmp installed on my desktop (Fedora 36), and when I control the application via PlexAmp on the phone (by connecting to it) - play and pause works fine. This is not headless!
The PlexAmp on the Raspberry Pi is headless, and this has the problem with play and pause controlled via the phone, as well as via the PlexAmp installation on my desktop - safe to say it is isolated to the headless install on the Raspberry Pi. (which I upgraded to 4.3 recently).
I hope this helps.
