How to connect the device using AT commands on the esp32 LilyGO T-SIM7600G to HiveMQ Cloud

[israsho]

I was following this user’s guide on arduino: Sim7600g-h mqtt at+cmqttconnect error, but I have an error in the following command:
AT+CSSLCFG?

+CSSLCFG: 0,4,3,1,300,“cacert.pem”,“clientcert.pem”,“clientkey.pem”,1,“”,0xFFFF
AT+CMQTTSTART
OK
//I copied the certificates from the link left by hivemq server.pem - Google Drive, assuming that the order is as follows: carcert,client,clientkey
+CMQTTTTSTART: 7 // What does number 7 mean?

#define uS_TO_S_FACTOR      1000000ULL  /* Conversion factor for micro seconds to seconds */
#define TIME_TO_SLEEP       30          /* Time ESP32 will go to sleep (in seconds) */

#define UART_BAUD           115200

#define MODEM_TX            27
#define MODEM_RX            26
#define MODEM_PWRKEY        4
#define MODEM_DTR           32
#define MODEM_RI            33
#define MODEM_FLIGHT        25
#define MODEM_STATUS        34

#define SD_MISO             2
#define SD_MOSI             15
#define SD_SCLK             14
#define SD_CS               13

#define LED_PIN             12

#define TINY_GSM_MODEM_SIM7600
#define TINY_GSM_RX_BUFFER 1024 // Set RX buffer to 1Kb
#define SerialAT Serial1

// See all AT commands, if wanted
#define DUMP_AT_COMMANDS


// set GSM PIN, if any
#define GSM_PIN ""

// Your GPRS credentials, if any
const char apn[]  = "internet.tigo.bo";     //SET TO YOUR APN
const char gprsUser[] = "tigo";
const char gprsPass[] = "tigo";

#include <TinyGsmClient.h>
#include <SPI.h>
#include <SD.h>
#include <Ticker.h>

#ifdef DUMP_AT_COMMANDS  // if enabled it requires the streamDebugger lib
#include <StreamDebugger.h>
StreamDebugger debugger(SerialAT, Serial);
TinyGsm modem(debugger);
#else
TinyGsm modem(SerialAT);
#endif


int counter, lastIndex, numberOfPieces = 24;
String pieces[24], input;


bool reply = false;

void modem_on() {
    /*
    The indicator light of the board can be controlled
    */
    pinMode(LED_PIN, OUTPUT);
    digitalWrite(LED_PIN, HIGH);

    /*
    MODEM_PWRKEY IO:4 The power-on signal of the modulator must be given to it,
    otherwise the modulator will not reply when the command is sent
    */
    pinMode(MODEM_PWRKEY, OUTPUT);
    digitalWrite(MODEM_PWRKEY, HIGH);
    delay(300); //Need delay
    digitalWrite(MODEM_PWRKEY, LOW);

    /*
    MODEM_FLIGHT IO:25 Modulator flight mode control,
    need to enable modulator, this pin must be set to high
    */
    delay(1000); //Need delay
    pinMode(MODEM_FLIGHT, OUTPUT);
    digitalWrite(MODEM_FLIGHT, HIGH);

    
  int i = 10;
  Serial.println("\nTesting Modem Response...\n");
  Serial.println("****");
  while (i) {
    SerialAT.println("AT");
    delay(500);
    if (SerialAT.available()) {
      String r = SerialAT.readString();
      Serial.println(r);
      if ( r.indexOf("OK") >= 0 ) {
        reply = true;
        break;;
      }
    }
    delay(500);
    i--;
  }
  Serial.println("****\n");
}

void setup() {
  Serial.begin(115200); // Set console baud rate
  SerialAT.begin(115200, SERIAL_8N1, MODEM_RX, MODEM_TX);
  delay(100);

  modem_on();
  if (reply) {
    Serial.println(F("***********************************************************"));
    Serial.println(F(" You can now send AT commands"));
    Serial.println(F(" Enter \"AT\" (without quotes), and you should see \"OK\""));
    Serial.println(F(" If it doesn't work, select \"Both NL & CR\" in Serial Monitor"));
    Serial.println(F(" DISCLAIMER: Entering AT commands without knowing what they do"));
    Serial.println(F(" can have undesired consiquinces..."));
    Serial.println(F("***********************************************************\n"));
  } else {
    Serial.println(F("***********************************************************"));
    Serial.println(F(" Failed to connect to the modem! Check the baud and try again."));
    Serial.println(F("***********************************************************\n"));
  }
}

void loop() {
  while (true) {
    if (SerialAT.available()) {
      Serial.write(SerialAT.read());
    }
    if (Serial.available()) {
      SerialAT.write(Serial.read());
    }  
    delay(1);
  }

}