Arduino DUE and Arduino NANO APC220 Serial Communication

How to Communication Due and Nano? I need help!!! I use this code but not working correctly. Nano send message DUE. DUE do not read message. but DUE send message nano. I saw the message nano.

I was tested two arduino nano. worked. :)))

void setup() {

Serial.begin(9600);
while (!Serial) {
;
}

Serial.println(“Goodnight moon!”);

}

void loop() {

if (Serial.available()) {
Serial.write(Serial.read());
}
}

void setup()
{
Serial.begin(9600); // match APC communication-rate
}

void loop()
{

Serial.println(“Send Message1”);
delay(1000);
Serial.println(“Send Message2”);
delay(1000);
Serial.println(“Send Message3”);
delay(1000);
Serial.println(“Send Message4”);
delay(1000);
}