Unable to connect to your database server using the provided settings

Hi,
This is the section from config/database.php of a project that is using sqlsrv driver.

PHP Code:

$db['mssql'] = array(
    'dsn'          => '',
    'hostname'     => 'hostname',
    'username'     => 'username',
    'password'     => 'secretpassword',
    'database'     => 'DATABASENAME',
    'dbdriver'     => 'sqlsrv',
    'dbprefix'     => '',
    'pconnect'     => FALSE,
    'db_debug'     => (ENVIRONMENT !== 'production'),
    'cache_on'     => FALSE,
    'cachedir'     => '',
    'char_set'     => 'utf8',
    'dbcollat'     => 'utf8_general_ci',
    'swap_pre'     => '',
    'encrypt'      => false,
    'compress'     => FALSE,
    'stricton'     => FALSE,
    'failover'     => array(),
    'save_queries' => FALSE
);