A timeout occured after 30000ms selecting a server using CompositeServerSelector

Question

I try to deploy my Mongo database in Mongolabs, everything works fine, and I create a new database. Please see my connectionstring.

    public DbHelper()
    {

        MongoClientSettings settings = new MongoClientSettings()
        {
            Credentials = new MongoCredential[] { MongoCredential.CreateCredential("dbname", "username", "password") },
            Server = new MongoServerAddress("ds011111.mongolab.com", 11111),
            //ConnectTimeout = new TimeSpan(30000)
        };

        Server = new MongoClient(settings).GetServer();

        DataBase = Server.GetDatabase(DatabaseName);

    }

but when I try to connect the database it's shows error like:

Ebon

Yeah, I have mistaken in connection string building, so the timeout error occurred. Please see the answer below. – Ebon

Possible duplicate of MongoDB C# 2.0 TimeoutException – Mingmingche

I had this error because the port in my connection string did not match the port in my local mongo db configuration and settings. Once they matched, this error ceased. – Tickler

@Tickler great – Ebon

Answer 1

I am replacing the connection string method in like below.

new MongoClient("mongodb://username:[email protected]:11111/db-name")

Now it's solved.

Please see the answer from Paul Lemke.

Ebon

Yep, MongoLab doesn't like new MongoSettings(new MongoUri("...")) – Succinylsulfathiazole

Why didn't you mark his answer as the solution? – Buhrstone

Answer 2

Add "?connect=replicaSet" to the end of your connection string if connecting to MongoLab.

new MongoClient("mongodb://username:[email protected]:11111/db-name?connect=replicaSet")

This JIRA ticket has some details: https://jira.mongodb.org/browse/CSHARP-1160

Basically the default is to connect to a replica set member. But MongoLab's Single-Node settings are actually a single node replica set and this causes us to not trust it. Appending ?connect=replicaSet to your connection string will force the driver to move into replica set mode and all will work.

Found that info here.

Incurrent

Answer 3

Make sure your current ip address is white-listed in mongo db server. If you change your internet provider new IP needs to be white-listed.

Boaten

@RamyDeeb Its not just for the user who posted it , but also for those who are facing similar issues and viewing relevant answers – Lallygag

@RamyDeeb the answer provided its also for others who has the same issue and can look for other possible solutions. Please, if you ever have another "solution", just add it, this platform is what it was built for! – Cryptology

exactly what happened with my azure service... – Basildon

Answer 4

Make Sure your auth db is set correctly.

I ran into this issue when I mentioned only the DB i wanted to connect to , and my auth db was different (other than admin db ).

The db-name in this line is considered as the auth DB .

new MongoClient("mongodb://username:[email protected]:11111/db-name?connect=replicaSet")

Then you can change the selected DB Later

mDb = mClient.GetDatabase(mongoDBName);

Haveman

What is the connect parameter in your connection string? I cannot find info on that in the Mongo docs. – Banns

Answer 5

Same Error Message but not encountered with a MongoLabs deployment.

I just encountered the same error listed in the title with an Asp.Net Core App. My issue was due to an IOC configuration issue.

In my IOC container, my wrapped MongoClient instance was configured with a dependency transient lifestyle.

Per The MongoDb C# Driver:

It is recommended to store a MongoClient instance in a global place, either as a static variable or in an IoC container with a singleton lifetime.

I promoted the lifestyle of my object to a singleton and it resolved the issue.

I am using:

• .Net Core 2.0
• Mongo C# Driver version 2.5
• Castle Windsor for my IOC version 3.3.0

Please reference the C# Driver Client section: http://mongodb.github.io/mongo-csharp-driver/2.5/reference/driver/connecting/#re-use

Mabelmabelle

Answer 6

Make sure the database username is also case sensitive. I ran into this issue because of case sensitivity of the username.

Photooffset

Answer 7

It's related with MongoDB connection error. Probably you don't have permissions or you didn't specify the allowed IPs in MongoDB. Please check for example in MongoDB Compose if you are able to connect with your MongoDB Atlas. If you won't be able to connect, that means that you have wrong MongoDB connection string.

Bloodmobile

Answer 8

In my case, while trying to execute the application with docker compose, I forget the environment variables. The problem was resolved by adding the correct environment variables.

Tannie

What environment variables have you added? – Biathlon

Those related to database connection and ASP NET environment, as I remember from now. Seeing the project now, I can see two: one of them is from MongoDb database connection; the another one is present in the main Docketfile, in API layer: ENV ASPNETCORE_URLS=http://+:5223 – Tannie

Answer 9

I had the same issue. I was able to connect to MongoDB Atlas Using MongoDb Compass, but using the same connection string in a C# project I got the error "A timeout occured after 30000ms selecting a server using CompositeServerSelector... ---> System.Net.Internals.SocketExceptionFactory+ExtendedSocketException (61): Connection refused 192.168.1.254:53".

In my case the problem was caused by my Internet provider router. Switching the connection to my iPhone's 4G hotspot solved the connection issue.

Sera

Answer 10

The port 10255 was blocked by my Internet provider/firewall rules. Opening this port at client side fixed the issue.

Marlowe

Answer 11

I had this issue and turned out the database server was 2 hours behind. Once I fixed its time, the timeout issue was resolved with it.

Flatways

Answer 12

I had the same issue where there is a replicaset with name rs0 and I didnt specify the replicaset

So this caused the CompositeServerSelector timeout.

"ConnectionString": "mongodb://server01:27017,server02:27017,server03:27017"

And this

"ConnectionString": "mongodb://server01:27017,server02:27017,server03:27017?connect=replicaSet"

Passing the actual replicaset name fixed it:

"ConnectionString": "mongodb://server01:27017,server02:27017,server03:27017?replicaSet=rs0"

Fungus

Answer 13

The mongo-connection-check tool helped me by showing that the mongodb atlas port could not be connected to. If the mongodb atlas UI does not offer to whitelist your current IP, it does not reliable mean that your IP is in fact whitelisted. So my fix was to reload the mongodb atlas UI and whitelist my current IP. The link to mongo-connection-check was mentioned in Having trouble connecting to Mongo DB from hosting server

Craven

Answer 14

I have to change the connection string adding +srv at the beginning:

mongodb://..... to mongodb+srv://.....

Whiten