Help with MySQL library code to connect to a remote database (LilyGo T-SIM7600X)

PsySc0rpi0n

Ok, so I have a Windows machine with the SQL database and MySQL Workbench 8.0. The database have 1 table with 1 row only, just for testing purposes.
Then, I have my laptop, running Debian and I can connect from this laptop to the Windows machine (where the database is) using mysql command line tool, either using root or another user.
The code I'm using in my LilyGo T-SIM7600X device is this:

#include <WiFi.h>
#include <MySQL_Connection.h>
#include <MySQL_Cursor.h>

#define SOUND_SPEED 0.034
#define CM_TO_INCH 0.039701

#define GOT_HERE() do {Serial.print('['); Serial.print(__LINE__); Serial.println(']'); Serial.flush();} while(0)

IPAddress server_addr(192, 168, 1, 157); // Server IP address

char user[] = "testuser";                          // MySQL user
char password[] = "testuser-passwd";    // MySQL password
char ssid[] = "Work_WiFi";                     // Wi-Fi SSID
char pass[] = "Work_WiFi_passwd";     // Wi-Fi password
char INSERT_DATA[] = "INSERT INTO sensorsdara (sensorsId, latitude, longitude, distance, weight, lastUpdate, description) VALUES ('%s', %.8f, %.8f, %d, %.1f, '%s', '%s')";

WiFiClient Client;
MySQL_Connection conn(&Client);
MySQL_Cursor* cursor;

const int trigPin = 13;
const int echoPin = 14;
long duration = 0;
float distanceInch = 0;

void setup() {
  Serial.begin(115200);
  Serial.println("Starting the system...");
  checkWiFi();
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
}

void loop() {
  int sensorsId = 1;  // Assuming sensorsId is an integer
  float latitude = 40.12236870;
  float longitude = -7.75648210;
  float weight = 98.5;
  int distance = 56;
  char timestamp[] = "19:22:37";
  char description[] = "Contentor XYZ, marca AAA"; 
  
  ReadData(&sensorsId, latitude, longitude, distance, weight, timestamp, description);
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  duration = pulseIn(echoPin, HIGH);
  distance = duration * SOUND_SPEED / 2;
  ReadData(&sensorsId, latitude, longitude, distance, weight, timestamp, description);
  delay(100);
  SendData(sensorsId, latitude, longitude, distance, weight, timestamp, description);
  Serial.println();
}

void ReadData(int* sensorsId, float latitude, float longitude, int distance,
              float weight, char timestamp[], char description[]){
  char mensagem[20];
  byte actual, i = 0;
  actual = 255;
  if(Serial.available() > 0){
    while (actual != 10){
      if(Serial.available() > 0){
        actual = Serial.read();
        mensagem[i] = (char) actual;
      }
    }
    i = 0;
    *sensorsId = atoi(strtok(mensagem, "|"));
    //*temp = atof(strtok(NULL, "|"));
  } 
}

void SendData(int sensorsID, float latitude, float longitude, int distance, float weight, char timestamp[], char description[]) {
  char query[256];
  char sensorsId[10] = "sensorABC";

  checkWiFi();

  Serial.print("Connecting to MySQL database... ");
  if (conn.connect(server_addr, 3306, user, password, "database_name")) {
    Serial.println("Connected successfully.");
    delay(1000);
    MySQL_Cursor *cur_mem = new MySQL_Cursor(&conn);
    
    // Prepare the SQL query
    sprintf(query, INSERT_DATA, sensorsId, latitude, longitude, distance, weight, timestamp, description);
    
    // Print the query for debugging purposes
    Serial.print("Executing query: ");
    Serial.println(query);
    
    // Execute the query
    if (cur_mem->execute(query)) {
      Serial.println("Query executed successfully, data inserted.");
    } else {
      Serial.println("Failed to execute query.");
    }
    
    // Free up memory used by the cursor
    delete cur_mem;
  } else {
    Serial.println("Failed to connect to MySQL database.");
  }

  conn.close();
}

void checkWiFi() {
  Serial.print("Checking WiFi connection... ");
  if (WiFi.status() != WL_CONNECTED) {
    Serial.println("Not connected. Trying to connect...");
    WiFi.disconnect();
    delay(1000);
    WiFi.begin(ssid, pass);
    
    while (WiFi.status() != WL_CONNECTED) {
      delay(500);
      Serial.print(".");
    }
    Serial.println("\nConnected to WiFi.");
  } else {
    Serial.println("Already connected to WiFi.");
  }
}

The issue is that the connection never happens, or at least the insertion of the data is never inserted into the database.
So, I went a bit deeper and started to add that known macro that tells us the line of code where the macro is used in the source code of the library MySQL_Connection.h to see where the code would hang and I came to the conclusion that the code hangs here:
https://github.com/ChuckBell/MySQL_Connector_Arduino/blob/067b345a3a9870d836bcfb89c4f709bf0561c8b8/src/MySQL_Connection.cpp#L87

So, this must be something related with authentication, although I can connect to the database using mysql command line tool from my laptop.

So, I need some help to try to figure out what may be wrong with the code or the authentication or maybe something wrong with the database settings/permissions
The part of the library source code I added the GOT_HERE(); macro is this:

while (retries--)
  {
    Serial.println("...trying...");
    Serial.print("Attempt: ");
    Serial.println(retries);
    connected = client->connect(server, port);
    GOT_HERE(); // We do reach here
    if (connected != SUCCESS) {
      GOT_HERE(); // We do not reach here
      Serial.print("...got: ");
      Serial.print(connected);
      Serial.println(" retrying...");
      delay(CONNECT_DELAY_MS);
    } else {
      GOT_HERE(); // We do reach here
      break;
    }
  }

  if (connected != SUCCESS){
      GOT_HERE(); // We do not reach here
      return false;
  }
  
  GOT_HERE(); // We do reach here
  read_packet();
  GOT_HERE(); // We do reach here
  parse_handshake_packet();
  GOT_HERE();
  Serial.print("User: "), Serial.println(user);
  Serial.print("Passwd: "), Serial.println(password);
  Serial.print("DB: "), Serial.println(db);
  send_authentication_packet(user, password, db);
  GOT_HERE(); // We do not reach here
  read_packet();
  GOT_HERE(); // We do not reach here
  if (get_packet_type() != MYSQL_OK_PACKET) {
    parse_error_packet();
    return false;
  }

I commented where the code reaches and where the code does not reach the macro and also added a couple of Serial.println() lines
Serial Monitor shows this:

beck lowis

It seems like your connection is working fine. If you're testing further, especially for your Food Website, try running a few simple queries from your Debian laptop using mysql to ensure everything works smoothly between machines.