How to fix 'Error: querySrv EREFUSED' when connecting to MongoDB Atlas?

Question

I am new to MongoDB 4.0.6 and tried to implement it into my website using Node/Express.js, but when I try to connect to mongodb+srv://${process.env.MONGOUSER}:${process.env.MONGOPASS}@main-03xkr.mongodb.net/main I'm getting this error:

{ Error: querySrv EREFUSED _mongodb._tcp.main-03xkr.mongodb.net at QueryReqWrap.onresolve [as oncomplete] (dns.js:199:19) errno: 'EREFUSED', code: 'EREFUSED', syscall: 'querySrv', hostname: '_mongodb._tcp.main-03xkr.mongodb.net' }

I've tried connecting to mongodb://localhost:27017/main, but this does seem work.

Here is the relevant code:

require('dotenv').config();
const mongoose = require('mongoose');

// Database
const uri = `mongodb+srv://${process.env.MONGOUSER}:${process.env.MONGOPASS}@main-03xkr.mongodb.net/main`;
const localURI = 'mongodb://localhost:27017/main';

var Project = require('./models/project');

mongoose.connect(uri, { useNewUrlParser: true });
const db = mongoose.connection;

db.once('open', () => console.log('Successfully connected to MongoDB'));
db.on('error', (e) => console.log(e));

// Routes
app.get('/', (req, res) => {
  Project.find({}, (e, projects) => {
    if (e) console.log(e);

    res.render('home.ejs', {
      projects: projects
    });
  });
});

So does anyone know how to fix this error and maybe explain what is happening here?

Yes, I have whitelisted every IP using `0.0.0.0/0` @VtoCorleone — Noodles, Apr 03 '19 at 16:08

Noodles · Accepted Answer · 2019-07-30T11:21:07.117

74

If you're encountering this error try to use the older connection string for Node.js 2.2.12 or later:

mongodb://<username>:<password>@main-shard-00-00-03xkr.mongodb.net:27017,main-shard-00-01-03xkr.mongodb.net:27017,main-shard-00-02-03xkr.mongodb.net:27017/main?ssl=true&replicaSet=Main-shard-0&authSource=admin&retryWrites=true

According to MongoDB, SRV is possibly not working due to Mongoose.

edited Jul 30 '19 at 11:21

answered Apr 11 '19 at 18:28

Noodles

3,888
2
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31

Thanks for the answer, it worked for me as well. But I would love to know why isn't it working with 3.0? – amine23 Mar 26 '20 at 12:58
2

When I asked the MongoDB staff, they said it might be because of Mongoose, but I don't know the specific answer. – Noodles Mar 26 '20 at 13:46
1

I encountered this error but due to inactivity of my website. The mongodb connection automatically paused the instance when there's no activity of the website. I resume the connection and all goes well. Cheers! – Grald Jul 10 '21 at 13:06

score 59 · Answer 2 · edited Sep 01 '19 at 20:08

59

I had this same error when I was connecting with Node version 3.0 or later and I resolved it by downgrading to 2.2.12 or later version:

edited Sep 01 '19 at 20:08

Samuel Philipp

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12
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answered Sep 01 '19 at 19:54

Joseph Kasule

699
5
3

1

This works although the "mongodb" package i am using from npm is at ^v3.5.7 which should be considered for "3.0 or later" connections. But the "3.0 or later" one works for my AWS EC2 instance just fine but not locally. local node -v -> 13.0.x AWS node -v -> 10.20.1 – kaushalop Jul 21 '20 at 04:29
Same here, Windows runs just fine but Linux with the same configuration doesn't (mongodb@3.6.8 node@14.15.4). Using the older connection string works for some reason. – Sjeiti Jun 15 '21 at 14:06

score 16 · Answer 3 · answered May 18 '21 at 18:09

16

In my case, it's mainly a DNS issue in mac, to resolve it, just add google DNS server under the DNS section in mac book pro settings:

8.8.8.8
4.4.4.4

answered May 18 '21 at 18:09

HMagdy

3,029
33
54

1

Thanks @HMagdy I was just looking for this. – Vikash May 29 '21 at 05:57
1

This worked for me. Macbook and it is shared coworking space wifi. No issue with my personal wifi though. – Mallikarjun Aug 31 '21 at 08:26
2

This work for me after resume my cluster. – ali sampson Mar 15 '23 at 11:14

score 15 · Answer 4 · answered Jul 24 '20 at 04:32

15

This error occurs sometimes when you are using MongoDB Atlas and lost your internet connectivity. You will not be able to access your database.

answered Jul 24 '20 at 04:32

Kamesh Kumar Singh

651
9
11

score 11 · Answer 5 · edited Sep 16 '20 at 03:24

11

Make sure to change the node version to 2.2.12:

enter image description here

And add IP address:

enter image description here

edited Sep 16 '20 at 03:24

4b0

21,981
30
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answered Sep 16 '20 at 02:49

MOHAMMED NABAWY

221
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2

This was my problem - the new unified connection string would sometimes work, sometimes not. It was extremely frustrating to troubleshoot. Went back to the old connection string format and it instantly worked again. – Layne Bernardo Jul 13 '21 at 09:19

score 5 · Answer 6 · edited Apr 19 '20 at 10:37

5

Pass option { useNewUrlParser: true, useUnifiedTopology: true } to the MongoClient constructor

const uri = "mongodb+srv://${process.env.MONGOUSER}:${process.env.MONGOPASS}@main-03xkr.mongodb.net/main"

mongoose.connect(uri, { useNewUrlParser: true, useUnifiedTopology: true })
    .catch(error => console.log(error));

edited Apr 19 '20 at 10:37

hoangdv

15,138
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answered Apr 18 '20 at 17:26

Abin Abbas

51
1
3

score 4 · Answer 7 · answered May 11 '22 at 07:29

4

In my case it was throwing this error due mongodb cluster auto paused because of prolonged inactivity. I just resumed it, then it started properly.

answered May 11 '22 at 07:29

Rohit Parte

3,365
26
26

score 3 · Answer 8 · answered Apr 03 '19 at 17:07

3

You have undefined in your connection string. I don't know if this is typo or not. But try changing

const uri = `mongodb+srv://undefined:${process.env.MONGOPASS}@main-03xkr.mongodb.net/main`;

to

const uri = `mongodb+srv://${process.env.MONGOUSER}:${process.env.MONGOPASS}@main-03xkr.mongodb.net/main`;

I use MongoAtlas for a project and that string (minus the undefined user) looks correct.

answered Apr 03 '19 at 17:07

VtoCorleone

16,813
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haha... interesting. I'd scrub that from your stack post just so people can't try and guess a password for your credentials. Can you try connecting to the instance through the CLI? https://docs.atlas.mongodb.com/mongo-shell-connection/ Just to test that your credentials and URL is correct? – VtoCorleone Apr 03 '19 at 17:39
Sorry for the late response. It does connect using the CLI, so I guess it must be something in my code. – Noodles Apr 11 '19 at 18:00

score 3 · Answer 9 · answered Sep 16 '19 at 04:19

3

In our case antivirus/firewall is blocking,

Try to disable antivirus/firewall and check again. hope it will work.

answered Sep 16 '19 at 04:19

Shaik Matheen

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1

My god. I had to disable Win10 firewall for atlas connection to work... – garenyondem Sep 23 '19 at 21:30

score 3 · Answer 10 · edited Jan 03 '21 at 11:30

Error: querySrv ESERVFAIL _mongodb._tcp.databasename-zcbag.mongodb.net
    at QueryReqWrap.onresolve [as oncomplete] (dns.js:202:19) {
  errno: 'ESERVFAIL',
  code: 'ESERVFAIL',
  syscall: 'querySrv',
  hostname: '_mongodb._tcp.databasename-zcbag.mongodb.net'
}

If the above code is your output then there is no error in your code. You have to check your network connection. Maybe you have to switch your network from the phone network to another or vice versa.

Hamada · Answer 11 · 2020-04-24T12:01:26.247

MongoClient.connect(
  "mongodb://USER:PASSWORT@mflix-shard-00-00-r5yfb.mongodb.net/test?ssl=true&replicaSet=mflix-shard-0&authSource=admin&retryWrites=true&w=majority",
  { useNewUrlParser: true, useUnifiedTopology: true },
)
  .catch(err => {
    console.error(err.stack)
    process.exit(1)
  })
  .then(async client => {
    await MoviesDAO.injectDB(client)
    await UsersDAO.injectDB(client)
    await CommentsDAO.injectDB(client)
    app.listen(port, () => {
      console.log(`listening on port ${port}`)
    })
  })

Maybe can works with MongoClient( not Mongoose )

score 1 · Answer 12 · answered Sep 21 '20 at 15:30

In my case, this error was happening when the DNS configuration in my TP-Link Router was missing.

I've installed OpenWRT firmware on it and forgot to adjust DNS settings.

I was able to open YouTube or any other website because that's not my main router, but could not connect to database.

It was an internet issue, like @Kamesh Kumar Singh said in his answer.

I think that this is not an usual answer for this question, but may help someone.

score 1 · Answer 13 · answered Oct 17 '20 at 17:38

1

This error occurs if you are not able to connect to mongoDB Atlas database. Your server runs successfully but you get this error while connecting to database. Make sure your internet connection is good and try again you won't see this error.

answered Oct 17 '20 at 17:38

Rajashekar Reddy

57
1
6

I also had the same case. – Prince Agrawal Dec 17 '20 at 08:45

score 1 · Answer 14 · answered Jul 25 '21 at 12:27

1

In my case, the issue occurred because MongoDB paused my cluster due to over 4 months of inactivity. After I logged in to my account and resumed the activity of the cluster, the issue was immediately resolved.

answered Jul 25 '21 at 12:27

Timothy

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1
6

score 1 · Answer 15 · answered Jul 27 '21 at 09:46

I solved mine by going into the MongoDB -> login -> databases -> connect -> connect your application (middle one) -> copy the code -> paste the code into the mongooseDB code in my .JS file:

const mongoose = require('mongoose');
require('dotenv/config');

mongoose
  .connect(process.env.THE_MONGO_DB_URL_GOES_HERE_IN_DOTENV_FILE, {
    useNewUrlParser: true,
    useUnifiedTopology: true,
    useCreateIndex: true,
  })
  .then(() => console.log("Database connected!"))
  .catch(err => console.log(err));

  const PostSchema = mongoose.Schema({
    email: String,
    password: String
  }, {strict: false});

  const DataEntry = mongoose.model('n26-users-collection', PostSchema); 

  module.exports = DataEntry;

Ezra Siton · Answer 16 · 2021-03-03T18:44:19.633

"Not in the root folder" scenario:

Create a .env file in the root directory of your project. https://github.com/motdotla/dotenv

One scenario for this error is to create dotenv .env file --NOT-- in the root folder (Under /src for example).

Than this code:

const url = `mongodb+srv://${process.env.DB_USER}:${
  process.env.DB_USER_PASSWORD
}@${process.env.DB_CLUSTER}.mongodb.net`;

console.log(url)

output:

mongodb+srv://undefined:undefined@undefined.mongodb.net

So the "undefined" URL connection:

const client = new MongoClient(url);

Throw 3 warnings:

(node:27240) UnhandledPromiseRejectionWarning: Error: querySrv ENOTFOUND _mongodb._tcp.undefined.mongodb.net at QueryReqWrap.onresolve [as oncomplete] (dns.js:207:19)

(node:27240) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag --unhandled-rejections=strict (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 1)

(node:27240) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

One more "close" scenario: .env in the root folder but the file is empty:

Solution

The first step to solve this issue is to console.log(url) and check if process.env returns the correct Connection String.

dotenv github readme: https://github.com/motdotla/dotenv#readme
Connect to a MongoDB Database Using Node.js : https://developer.mongodb.com/quickstart/node-connect-mongodb/

score 0 · Answer 17 · answered Mar 15 '23 at 12:17

For the most part this error occurs when there is a mongodb driver and comnnection string mismatch. Ensure that use the conncetion string and its equivalent driver as specified in the Mongodb atlas connect section. Important Tip, dont use the latest mongodb driver. Use the previous version. You can acert conncetion issues easily.

How to fix 'Error: querySrv EREFUSED' when connecting to MongoDB Atlas?

17 Answers17

"Not in the root folder" scenario:

Solution

Linked

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