Install some missing packages

apt-get install pulseaudio pulseaudio-module-bluetooth pavucontrol bluez-firmware blueman

Set config

echo "AutoConnect=true" >> /etc/bluetooth/main.conf

Restart service

service bluetooth restart

Kill pulseaudio

killall pulseaudio

Fix a2dp profile

touch /etc/pulse/client.conf
cat <<EOF >> /etc/pulse/client.conf
autospawn = no
daemon-binary = /bin/true
EOF

chown Debian-gdm:Debian-gdm /etc/pulse/client.conf

rm /etc/pulse/.config/systemd/user/sockets.target.wants/pulseaudio.socket

echo "load-module module-switch-on-connect" >> /etc/pulse/default.pa

and reboot

Run pavucontrol as root

sudo pavucontrol

And do to Output > Show "All Output Devices" > Select A2DP