Bluetooth speaker pairs but sound doesn't work

Question

My speaker pairs with Ubuntu 14.04, but sound doesn't work and there is a lock near the bluetooth indicator. I tried this solution without success:

PulseAudio can not load bluetooth module

Answer 1

Copied from Question owner's comments from the question.

I solved in this way. I have installed pavucontrol. In terminal:

sudoedit /etc/bluetooth/audio.conf

Add these lines:

[General] 
Disable=Socket
Enable=Media,Source,Sink,Gateway

Save and exit from the editor

Then:

sudo service bluetooth restart

Cancel bluetooth speaker setup and set it up again.