Audio AudioSource file.Play() does not play the file

I have a few AudioSources of which one is the background music for my Scene.
When the character dies/wins I wanted to stop the background music and play an appropriate audio.
I do this like this:

Code (CSharp):

1. loseSound.volume = ambientSound.volume;
2. ambientSound.volume = 0;
3. ambientSound.Stop();
4. loseSound.Play();

But no sound is played. The ambientsound stops but the other doesnt start.

Thanks in advance for any help.

 

We'll need to see a bit more code than that ... how are ambientSound and loseSound defined? What objects are they referring to? Are they definitely assigned to the correct (and 2 different) audiosources?