EDIT: Problem solved 🙌 (check out answer below)
I got bluetooth headphones almost two years ago and Poweramp eight years ago, and have had no problem with using the headphones with the app before.
But a couple of weeks (maybe a month) ago, it started to not work properly. The sound and everything else works great, but if I pause Poweramp using the play/pause button on the headphones, I can’t start it up again with the button. Poweramp now also disappears from the lock screen when I pause, so I then have to unlock the screen, and open up Poweramp to start again where I paused.
I can pause and un-pause using the headphone button when I use my podcast app, so the problem doesn’t seem to be universal for the headphones.
If I un-pause right after having paused, there’s no problem and the music starts right back up again. But even a 10 second pause is enough for me to not be able to un-pause. There is no problem if the screen is unlocked, I’ve tried pausing and waiting a full five minutes before I un-pause, and it starts right back up.
I’ve tried “forgetting” the headphones and re-pairing them to the phone, I’ve tried rebooting the phone, I’ve tried un-checking the “react to buttons” headphone setting in Poweramp and re-checking it (after a reboot), but none of it has made any difference.
The problem might have started when I updated the Android version on my phone, but I’m not sure. It’s the only change I have made to headphones, phone or app in a while, but it might be a coincidence since I’m not definitely sure if the problems started right when I updated
Poweramp build number -- v3-build-882-arm64-play [882004-437be2ab]
Device model -- OnePlus 6T
Android version -- 10.3.5