Client connecting to multiple machines via foreach

Question

inside a multidimensional array, created by a mysql query, I have saved the connection parameters to multiple opcua machines. I believe the problem is the async functions inside the loop, but I don't know how to fix it.

When I run the script, no sessions are started and this error is returned

myprj/node-opcua-assert/dist/index.js:11
        const err = new Error(message);
                    ^
Error
    at assert (myprj/node-opcua-assert/dist/index.js:11:21)
    at OPCUAClientImpl._createSession (myprj/node-opcua-client/dist/private/opcua_client_impl.js:856:40)
    at OPCUAClientImpl.createSession (myprj/node-opcua-client/dist/private/opcua_client_impl.js:273:14)
    at OPCUAClientImpl.createSession (myprj/thenify/index.js:65:46)
    at OPCUAClientImpl.createSession (myprj/node-opcua-client/dist/private/opcua_client_impl.js:267:25)
    at myprj/thenify/index.js:72:10
    at new Promise (<anonymous>)
    at OPCUAClientImpl.createSession (myprj/thenify/index.js:70:12)
    at myprj/read_node.js:8

The code is:

    
/*
    Here is the code not listed for import settings and settings connection database
*/

const endpointUrl = config.endpointUrl;
const opcua = require("node-opcua");
const ping = require('ping');
const {
    AttributeIds,
    OPCUAClient
} = require("node-opcua");
const chalk = require("chalk");
const mysql = require('mysql2');

/*receive arguments*/

var argvs = process.argv.slice(2);
var args = [];
argvs.forEach(function (val, index, array) {
    var arg = val.split('=');
    args[arg[0]] = arg[1];
});

/*
Db connection
*/

var con = mysql.createConnection(config.mysql);

con.connect(function(err) {
    if (err) throw err;
    console.log(chalk.green("DB Connected!"));
});

/*
Reading machine->recipes->nodes
*/

;(async () => {
    try {

        var sql = "";
        sql = "SELECT * FROM machine ...";

        con.query(sql, function(err, machines) {

            if (err) throw err;

            /*
            Machine list
            */

            var m = 0;
            machines.forEach(async machine => {
                
                /*
                Check if machine is alive
                */              

                let HostInfo = await ping.promise.probe(machine.ip);
                console.log(HostInfo.alive);

                if(HostInfo.alive)
                {
                    console.log('Host ' + machine.ip + ' raggiungibile!');

                    var endpointUrl = machine.ip + ':' + machine.port;

                    console.log(endpointUrl);

                    client = OPCUAClient.create({
                        endpointMustExist: false,
                    });
            
                    console.log(" connecting to ", chalk.cyan(endpointUrl));
                    await client.connect(endpointUrl);
                    console.log(" connected to ", chalk.green(endpointUrl));

                    session = await client.createSession();
                    console.log(" session created".yellow);

                    var sql = "";
                    sql = "SELECT * FROM machine_recipes...";

                    /*
                    Machine recipes
                    */                  

                    con.query(sql, function(err, machine_recipes) {

                        if (err) throw err;

                        machine_recipes.forEach(async machine_recipe => {

                            /*
                            Machine recipes NODES to check
                            */

                            var sql = "";
                            sql = "SELECT * FROM machine_recipes_nodes...";

                            con.query(sql, function(err, nodes) {

                                var i = 0;
                                nodes.forEach(async node => {

                                    var params = JSON.parse(node.params);

                                    var dataValues  = await session.read([{
                                        nodeId: params.unitid
                                    }]);

                                    var node = params.unitid;
                                    var value = dataValues [0].value.value;
                                    
                                    
                                    /*
                                        Saving value in database...
                                    */

                                });
                            });
                        });
                    });
                }

                m++;
            });
        });

    } catch (err) {
        console.log('error !', err.message);
    }
})();

Thanks for help