无法在服务器上使用PHP创建MySQL数据库？

I am just trying to create database using PHP but not creating.It giving me following error :

Access denied for user 'user'@'localhost'

I am using cPanel ,where i created a user with all privileges & this user assigned to a specific database

I am working on SaaS Application (i.e. multiple database & single codebase).

Please help me to solve this problem.

Code I am using

   $dbhost = 'localhost:3306';
   $dbuser = 'xyz';
   $dbpass = 'xyz123';
   $conn = mysql_connect($dbhost, $dbuser, $dbpass);

   if(! $conn ) {
      die('Could not connect: ' . mysql_error());
   }

   echo 'Connected successfully';

   $sql = 'CREATE Database test_db';
   $retval = mysql_query( $sql, $conn );

   if(! $retval ) {
      die('Could not create database: ' . mysql_error());
   }

   echo "Database test_db created successfully
";
   mysql_close($conn);