My default Debian install had an issue with the headphones not working. To resolve it I needed to install the pulse audio bluetooth module and restart the service:
sudo apt-get install pulseaudio-module-bluetooth
pulseaudio -k
pulseaudio --start
sudo apt-get install pulseaudio-module-bluetooth
pulseaudio -k
pulseaudio --start
sudo apt-get install pulseaudio-module-bluetooth pulseaudio -k pulseaudio --start