Cannot read/write on a MongoDB Atlas database usin

I have a new sandbox cluster on MongoDB Atlas that I am connecting to with mongoose on a Node.js server. This is the code I'm using to connect:

const mongoDbUrl =
  `mongodb+srv://${username}:${password}@mydb-sandbox-12345.mongodb.net/testdb`

mongoose.connect(mongoDbUrl)
const connection = mongoose.connection

connection.on('connected', () => {
  console.log('Connected to mongodb')
})

In the Atlas dashboard I have a readWriteAnyDatabase user that I am authenticating with. Authentication works as expected. I am able to connect to the database and no error is thrown on the connection. I can confirm this by removing a character in the password - authentication fails and I'm unable to connect.

The problem is when I try to insert documents.

const UserModel = require('./models/User')

UserModel.create({
  name: 'Hello Atlas'
})

I get the following error:

MongoError: not authorized on admin to execute command {
insert: "users",
  documents: [
    [{
      name Hello Atlas
    } {
      _id ObjectIdHex("5aa17933d72d25730a340611")
    } {
      __v 0
    }]
  ],
  ordered: false
}

As far as I know the user I'm authenticating with should have permission to read and write on the database I'm connecting to. The other part I don't understand is that the error shows that it's trying to write to admin even though my url is connecting to testdb.

Cheers!

Not sure if you have seen this post, but it could be because you are on a free cluster? Hope this helps.

UPDATE

I looked into the problem further and reproduced it on my own. I got the same error. However, I noticed that at one point Atlas provided me with a choice of connection strings. I went back to that page and chose I am using driver 3.4 or earlier.

The connection string looks like this:

const mongoDbUrl = `mongodb://${username}:${password}@cluster0-shard-00-00-1wntz.mongodb.net:27017,cluster0-shard-00-01-1wntz.mongodb.net:27017,cluster0-shard-00-02-1wntz.mongodb.net:27017/testdb?ssl=true&replicaSet=Cluster0-shard-0&authSource=admin`;

It worked with that connection string.

It looks like the free version of MongoDB Atlas launches with v3.4