Sim7600 and arduino won't connect

Projects General Guidance
8

The arduino is supposed to make a phone call through the sim HAT as shown through the code shown above, presumably through the TX RX connections

  Serial.begin(9600);
  sim7600.PowerOn(POWERKEY);
  sim7600.PhoneCall(phone_number);

This is the code for the poweron and phonecall functions

/**************************Power on Sim7x00**************************/
void Sim7x00::PowerOn(int PowerKey = powerkey){
   uint8_t answer = 0;

  Serial.begin(9600);

  // checks if the module is started
  answer = sendATcommand("AT", "OK", 2000);
  if (answer == 0)
  {
    Serial.print("Starting up...\n");
    
    pinMode(PowerKey, OUTPUT);
    // power on pulse
    digitalWrite(PowerKey, HIGH);
    delay(500);
    digitalWrite(PowerKey, LOW);
    
    // waits for an answer from the module
    while (answer == 0) {     // Send AT every two seconds and wait for the answer
      answer = sendATcommand("AT", "OK", 2000);
	  delay(1000);
    }

  }

  delay(5000);

  while ((sendATcommand("AT+CREG?", "+CREG: 0,1", 500) || sendATcommand("AT+CREG?", "+CREG: 0,5", 500)) == 0)
    delay(500);
}

/**************************Phone Calls**************************/
void Sim7x00::PhoneCall(const char* PhoneNumber) {
  char aux_str[30];

//  Serial.print("Enter the phone number:");

//  scanf("%s", PhoneNumber);

  sprintf(aux_str, "ATD%s;", PhoneNumber);
  sendATcommand(aux_str, "OK", 10000);

  // press the button for hang the call 
  //while (digitalRead(button) == 1);

  delay(20000);

  Serial.println("AT+CHUP");            // disconnects the existing call
  Serial.print("Call disconnected\n");
}

/**************************SMS sending and receiving message **************************/

I'm guessing it stalls at the answer = sendATcommand("AT", "OK", 2000); line

The connections are based off this link of a connected older version of the sim

The gray wire is removed in my connections because pwr and 3.3v pins on the hat are jumpered together which turns it on automatically.