SetMusicOnHold application is deprecated and will be removed

Hi guys!
I have freePBX 2.11.0.38 and I can’t get music on hold to work! I see that music on hold is starting but I get no sound… the only warning I get is

> SetMusicOnHold application is deprecated and will be removed.

The problem is not the audio file because if I use it as announcement the audio works just fine.
What can the problem be?