Play audio when screen is off

I created a timer that should play a song after 1 minute but it is only working when the screen is on/unlocked, I activated background support for media but the sound is still not playing.

Project type: Web/TAU for smartwatch Galaxy Active 2/5.5
Source code:

Along with enabling background support also define the category like below,

<tizen:background-category value="media"/>

Please check this

Thank you