SMTP authentication password not accept by the framework

[eluser]Unknown[/eluser]
I got something like “Ssd$12^” as SMTP server password but when I try to send mails by using that password framework gives blank white page. is that SMTP password should only contain alphanumeric characters?

[eluser]Flemming[/eluser]
Codeigniter won't care what your SMTP password is! Perhaps you could post your code - it's likely there's a bug in it!

[eluser]Unknown[/eluser]
here is the code my CI_Email class variables,

i have changed the smtp host and user name as security reasons here but the thing is when i use another smtp server with alphanumeric user name and password same script works fine. I'm using codeignitor 1.5.2 version.

var $useragent = "Code Igniter";
var $mailpath = "/usr/sbin/sendmail";
var $protocol = "smtp";
var $smtp_host = "mail.servename.com";
var $smtp_user = "username";
var $smtp_pass = "Ssd$12^";
var $smtp_port = "25"; // SMTP Port
var $smtp_timeout = 30; // SMTP Timeout in seconds
var $wordwrap = TRUE; // true/false Turns word-wrap on/off
var $wrapchars = "76"; // Number of characters to wrap at.
var $mailtype = "html"; // text/html Defines email formatting
var $charset = "utf-8"; // Default char set: iso-8859-1 or us-ascii
var $multipart = "related"; // "mixed" (in the body) or "related"
var $alt_message = ''; // Alternative message for HTML emails
var $validate = FALSE; // true/false. Enables email validation
var $priority = "3"; // Default priority (1 - 5)
var $newline = "\r\n";
var $bcc_batch_mode = FALSE;
var $bcc_batch_size = 200;
var $_subject = "";
var $_body = "";
var $_finalbody = "";
var $_alt_boundary = "";
var $_atc_boundary = "";
var $_header_str = "";
var $_smtp_connect = "";
var $_encoding = "8bit";
var $_safe_mode = FALSE;
var $_IP = FALSE;
var $_smtp_auth = TRUE;
var $_replyto_flag = FALSE;
var $_debug_msg = array();
var $_recipients = array();
var $_cc_array = array();
var $_bcc_array = array();
var $_headers = array();
var $_attach_name = array();
var $_attach_type = array();
var $_attach_disp = array();
var $_protocols = array('mail', 'sendmail', 'smtp');
var $_base_charsets = array('iso-8859-1', 'us-ascii');
var $_bit_depths = array('7bit', '8bit');
var $_priorities = array('1 (Highest)', '2 (High)', '3 (Normal)', '4 (Low)', '5 (Lowest)');