title: Codeigniter error Unable to connect to MongoDB: Failed to connect: auth failed
body: <p>I am trying to connect to a mongodb database 'exam' using codeigniter mongodb library Codeigniter-mongo-library-master. I have created an user for this db using </p>
  
  <pre><code>db.createUser({ user: "root",
    pwd: "root",
    roles: [
      { role: "readWrite", db: "exam" },
     ]
  }}
  </code></pre>
  
  <p>It was successful.</p>
  
  <p>Then, when I tried to connect to this database in codeigniter using :</p>
  
  <pre><code>$config['mongo_db']['default']['no_auth'] = FALSE;
  $config['mongo_db']['default']['hostname'] = 'localhost';
  $config['mongo_db']['default']['port'] = '27017';
  $config['mongo_db']['default']['username'] = 'root';
  $config['mongo_db']['default']['password'] = 'root';
  $config['mongo_db']['default']['database'] = 'exam';
  </code></pre>
  
  <p>I got an error as shown below:</p>
  
  <blockquote>
    <p>Unable to connect to MongoDB: Failed to connect to: localhost:27017: Authentication failed on database 'exam' with username 'root': auth failed.</p>
  </blockquote>
  
  <p><strong>I am using php version 5.5.12 and mongodb driver php_mongo-1.5.1-5.5-vc11-x86_64.dll on Windows 7.</strong></p>
  
  <p>Can I get some help in solving this problem?</p>