Nox player sound not working?

I just installed Nox Player with Android 4.4.2 and at first, its sound was working. I played some games, but after some hours as I closed it and restarted it, since then at starting the sound first played, and then in 2 to 3 mins it goes off. To listen to the sound again, I have to restart the player, and then again in 2 to 3 mins, it does the same. Any solutions?