mongoose wont connect to ec2 mongodb instance - node.js

Question

i'm trying to create a node.js server that connect to my mongodb hosted on ec2 instance. I'm doing like this :
mongoose.connect("mongodb://username:password#ec2-xx-xx-xxx-xxx.eu-central-1.compute.amazonaws.com:27017/dbname");
db.on('error', err => {
console.log('Mongoose default connection error:', err);
db.close();
});
db.once('open', () => {
console.log(`Mongoose default connection open`);
});
But it keep saying me this error :
Mongoose default connection error: { MongoError: failed to connect to server [xxx] on first
connect [MongoError: connect ETIMEDOUT xxx:27017]
at Pool.<anonymous> (/Users/jmisiti/hm-landing/node_modules/mongodb-core/lib/topologies/server.js:336:35)
at emitOne (events.js:115:13)
at Pool.emit (events.js:210:7)
at Connection.<anonymous> (/Users/jmisiti/hm-landing/node_modules/mongodb-core/lib/connection/pool.js:280:12)
at Object.onceWrapper (events.js:318:30)
at emitTwo (events.js:125:13)
at Connection.emit (events.js:213:7)
at Socket.<anonymous> (/Users/jmisiti/hm-landing/node_modules/mongodb-core/lib/connection/connection.js:189:49)
at Object.onceWrapper (events.js:316:30)
at emitOne (events.js:115:13)
at Socket.emit (events.js:210:7)
at emitErrorNT (internal/streams/destroy.js:62:8)
at _combinedTickCallback (internal/process/next_tick.js:102:11)
at process._tickCallback (internal/process/next_tick.js:161:9)
name: 'MongoError',
message: 'failed to connect to server [xxx] on first connect [MongoError: connect ETIMEDO
UT xxx:27017]' }
My connection string is 100% sure it works. My mongoose version work great with my mongodb version. Any idea ? :)
PS : Ports are open on 27017 and there's already one of my aws instance using my mongodb. So i'm sure it work.

Answer 1

Make sure that you have registered 27017 port in Outbound ports In the EC2 security group.
Then try to access the DB. and if you have already added port and still experiencing the error then check if you MongoDB process is running as a service(i.e. in the background). If not then follow this procedure

Answer 2

Got it. I can't connect from my localhost to my mongodb server (Don't know why) but when i'm connecting to my mongodb server from my ec2 instance it work. So it's fine :)