The Light control program is not working. The light and the buzzer doesn’t turn on when I press the ON button. It was working fine a few moments ago. I tried changing the pin from 0 to other pins, still not working. I also tried using both analog and digital output. I double checked the code and the connections. What could be the issue 
check the code. Change the pin number in the code
Hello , @abhi2001
Here this might help you better understand the code, : Controlling Buzzer via Bolt IoT - Hackster.io
Also check the instructions you would have mentioned wrong pin numbers in the code.