PostgreSQL are not connected

Question

My Web site that using PostgreSQL not working on Heroku.

It's working at my PC own(ex.npm start = node index.js).

But on Heroku, it's not working.

It's my code.

function dbconnect(params, groupFlg) {
return new Promise(function(resolve, reject){
    const pool = pg.Pool(
        {
            connectionString: process.env.DATABASE_URL,
            ssl: true,
        }
    );
    params = params.split(/\s/);
    var queryText = 'SELECT * FROM movies WHERE (movieperson LIKE '%test%' OR movietitle LIKE '%test%') ORDER BY movieid DESC;';
    var query = {
        text: queryText
    };
    console.log("query: " + query.text);
    pool.connect(function (err, client, done) {
        if (err) {
            console.error(err.stack);
        } else {
            console.log("else 132");
            client.query(query.text)
                .then(res => {
                    done();
                    var resultHTML = "";
                    for (let i = 0; i < res.rows.length; i++) {
                        resultHTML += makeHTML(res.rows[i]);
                    }
                    resArray = res.rows;
                    client.end();
                    if (resultHTML == "") {
                        resultHTML = "not looking";
                    }
                    resolve(resultHTML);
                })
                .catch(e => console.error(e.stack));
        }
    });
    pool.end();
});
}