Express app getting disconnected right after the connection - mysql

Question

I created a rest api with Express. on my server.js the i have my mysql connection.. though the connection is made at first. It's working on my local machine properly but when i deployed on AWS EC2 service then i am facing this problem..
server.js
var mysql = require('mysql');
var connection = mysql.createConnection({
host: 'localhost',
user: 'myusername',
password: 'mypassword',
database: 'mydatabasename'
});
connection.connect(function (err) {
if (err) throw err;
console.log('connected!');
});
module.exports = connection;
i tried pm 2 handledisconnect() following other project function none worked.getting following error...
restapi#0.0.0 start /home/bcs_quiz_console/bcs-preparation-backend/restapi
npm start
connected!
events.js:180
throw er; // Unhandled 'error' event
^
Error: Connection lost: The server closed the connection.
at Protocol.end (/home/bcs_quiz_console/bcs-preparation-backend/restapi/node_modules/mysql/lib/protocol/Protocol.js:112:13)
at Socket. (/home/bcs_quiz_console/bcs-preparation-backend/restapi/node_modules/mysql/lib/Connection.js:97:28)
at Socket. (/home/bcs_quiz_console/bcs-preparation-backend/restapi/node_modules/mysql/lib/Connection.js:525:10)
at Socket.emit (events.js:208:15)
at endReadableNT (_stream_readable.js:1168:12)
at processTicksAndRejections (internal/process/task_queues.js:77:11)
Emitted 'error' event at:
at Connection._handleProtocolError (/home/bcs_quiz_console/bcs-preparation-backend/restapi/node_modules/mysql/lib/Connection.js:426:8)
at Protocol.emit (events.js:203:13)
at Protocol._delegateError (/home/bcs_quiz_console/bcs-preparation-backend/restapi/node_modules/mysql/lib/protocol/Protocol.js:398:10)
at Protocol.end (/home/bcs_quiz_console/bcs-preparation-backend/restapi/node_modules/mysql/lib/protocol/Protocol.js:116:8)
at Socket. (/home/bcs_quiz_console/bcs-preparation-backend/restapi/node_modules/mysql/lib/Connection.js:97:28)
[... lines matching original stack trace ...]
at processTicksAndRejections (internal/process/task_queues.js:77:11) {
fatal: true,
code: 'PROTOCOL_CONNECTION_LOST'
}
Thank anyone who can help in advance..