ExpressJS API crashes with Error read ECONNRESET

Question

If i activate a screen on my debian server with my express js api it will crash after a few hours with this error:

Error: read ECONNRESET
  File "internal/stream_base_commons.js", line 209, col 20, in TCP.onStreamRead
  File "internal/async_hooks.js", line 130, col 17, in TCP.callbackTrampoline

I created a pool in my Express JS application but it crashes, when I start my Debian screen with the Express JS application it crashes after a few hours if I don't use the API.

Please help me, I don't know how to fix, I think it's the firewall but I don't know. It can also be a configuration on my mysql.

const pool = mysql.createPool({
    host: 'localhost',
    user: 'user',
    database: 'database',
    password: 'password',
    connectionLimit: 10,
});

I added on every mysql request this code:

pool.getConnection((err, connection) => {
        if (err) {
          console.log(err);
          return res.status(400).send({
            msg: err
          });
        }

and on the end

connection.release();