Actually there are two points for connection to S1,2,3,4 ports,
Previously I had connected that point but i thought it could have been damaged so i changed the port and connected that ESC with different S4 point, which is located just below the white connection pad
Actually, I bought the ESC's from local market so I am attaching the photos of ESC
but when i was setting up the configuration for motor signal, none of the signal were working until I put it at the PWM signal for motor ESC
then 3 motors are working completely fine, but the 4th one is not...