Array function is not working [SOLVED]

You will have to reverse all logic.

void Sensor_Trigger()
{
  bool isWithin57 = false;
  for (int sonarCnt = 0; sonarCnt < SONAR_NUM; sonarCnt++)
  {
    if (sonar[sonarCnt].ping_cm() < 57)
    {
      isWithin57 = true;
    }
  }

  // if any of the sensors sensor measures less than 57
  if (isWithin57 == true)
  {
    Motor_Driver_1_RS.backward();
    Serial.println("Motor Driver 1 L/S is ON - Forward");
    delay(500);
    Motor_Driver_1_RS.stop();
    Serial.println("Motor Driver 1 L/S is OFF");
  }
}