ERROR CONNECTION | CDK Error: Connection refused (generic:111) (no replies)

Hi !
I'm sorry for my english, I'm french. I will try to be clear.

I have a problem with MySQL Connector/C++ 8.0.

When I try to connect my program to the session that I created for, my connection is refused with the error : CDK Error: Connection refused (generic:111)

I am working on Ubuntu 18.04 LTS.

My code is short, I only want to try a connection :

// Standard library
#include <iostream>

// MySQL Library
#include <mysqlx/xdevapi.h>

using namespace std;
using namespace mysqlx;

// Main entry point
int main(int argc, char ** argv)
{
  Session xoroseds_session("localhost", 33060, "xoroseds_api", "****");
  Schema db(xoroseds_session, "XOROSEDS_TEST");
  
  return 0;
}

I got the port from MySQL "itself" so I know that the right port is 3306 but when I try it, my error is CDK Error: unexpected message
and by the way a core dumped error... So I use 33060.

Thanks