Unity won't play any sound

I attached a desert ambience wav file to the main camera and set it on loop and play on awake. When I test my game on my Android device (Jelly Bean 4.3), it won’t play the sound but when I hit the multitask button and switch back to the game, the sound will play!

What am I facing?

Are you sure you have audio listener? You can also try 2D sound instead. Or you can try a simple script with OneShotAudio.