MongoDB can connect from mongo client but not from C# driver

Question

This thing will make me go crazy now. I'm trying to get it to work for 3 hours without any result. I installed mongodb 2.8rc4. I created a user account in admin db. I can connect to mongod using mongo localhost/agp -u dato0011 -p "MyPassword". I can authenticate it via db.auth, but for an unknown reason, this thing doesn't work from C# driver.

Connection string is mongodb://dato0011:MyPWD@localhost/agp

I initialize the db with the following code:

        var client = new MongoClient(ConfigurationManager.ConnectionStrings["Default"].ConnectionString);
        var server = client.GetServer();
        var db = server.GetDatabase("agp");

but when I try save, I get an exception saying:

Unable to connect to server 192.168.0.100:27017: Invalid credential for database 'agp'..

and deep below inner exceptions, there's this message:

{ "authenticate" : 1, "user" : "dato0011", "nonce" : "fc65b3c269560533", "key" : "35589d31830b76c72358343bc054105f" }

and this

{"Command 'authenticate' failed: auth failed (response: { \"ok\" : 0.0, \"errmsg\" : \"auth failed\", \"code\" : 18 })"}

Anyone has any idea what am I doing wrong? Thanks.

UPDATE

Don't know if it will help, but here's the code that throws exception:

Users.Save(user);

where Users is

Users = db.GetCollection<User>("users", WriteConcern.W1);

UPDATE 2 Apparently the exception message is a bit misleading. The driver does connect to mongod, but it can't authenticate for an unknown reason. username and password parameters are passed correctly. Here's the user in admin db.

> db.system.users.find().toArray()
[
        {
                "_id" : "agp.dato0011",
                "user" : "dato0011",
                "db" : "agp",
                "credentials" : {
                        "SCRAM-SHA-1" : {
                                "iterationCount" : 10000,
                                "salt" : "GjlDJOiKf2Xn1VO/1MhWXA==",
                                "storedKey" : "vAi30QZLFkCZf6ISm5TIfIWPwZY=",
                                "serverKey" : "DBmbbRLrLXEIxFCuZ52VaSnRWwo="
                        }
                },
                "roles" : [
                        {
                                "role" : "readWrite",
                                "db" : "agp"
                        },
                        {
                                "role" : "dbAdmin",
                                "db" : "agp"
                        }
                ]

Answer 1

Use MongoCredentials on MongoClientSettings -

    string username = "user";
    string password = "password";
    string mongoDbAuthMechanism = "SCRAM-SHA-1";
    MongoInternalIdentity internalIdentity = 
              new MongoInternalIdentity("admin", username);
    PasswordEvidence passwordEvidence = new PasswordEvidence(password);
    MongoCredential mongoCredential = 
         new MongoCredential(mongoDbAuthMechanism, 
                 internalIdentity, passwordEvidence);
    List<MongoCredential> credentials = 
               new List<MongoCredential>() {mongoCredential};


    MongoClientSettings settings = new MongoClientSettings();
    // comment this line below if your mongo doesn't run on secured mode
    settings.Credentials = credentials;
    String mongoHost = "127.0.0.1";
    MongoServerAddress address = new MongoServerAddress(mongoHost);
    settings.Server = address;

    MongoClient client = new MongoClient(settings); 

similar: Error on MongoDB Authentication

Answer 2

I was also having the same problem and in my case as I read the server log.Its the problem because of the "authSchema version" of mongo so all you have to follow are the following steps and it'll start working

• Restart the mongod without --auth option

• Now use the following on the client

  mongo
  use admin;
  db.system.users.remove({})    
  db.system.version.remove({})
  db.system.version.insert({ "_id" : "authSchema", "currentVersion" : 3 })
  

*create your user again and restart mongod in --auth mode