[horde] Please help to debug! Login failed for some reason.

[prince]

I have been trying to fix the Horde Login problem I have, for days. 
Whenever I try to login I get the following error.
"Login failed for some reason. Most likely your username or password was 
entered incorrectly."

I have courier-imap and mysql installed and the imap login is verified by 
telnetting to port 143. But, I couln't login thru horde.

I tried both IMAP and cyrus as the server, but is of no use. My php version 
is 4.2.2. Does the maildomain in the following has to be the same as the 
server hosting the horde and imap?

****
How do I trace/debug to find where the authentication is getting failed and 
why?
****

This is the entry from server.php. 

$servers['imap'] = array(
    'name' => 'IMAP Server',
    'server' => 'localhost',
    'protocol' => 'imap/notls',
    'port' => 143,
    'folders' => 'mail/',
    'namespace' => '',
    'maildomain' => 'xxx.com',
    'smtphost' => 'localhost',
    'realm' => '',
    'preferred' => 'true'
);

$servers['cyrus'] = array(
    'name' => 'Cyrus IMAP Server',
    'server' => 'localhost',
    'protocol' => 'imap/notls',
    'port' => 143,
    'folders' => '',
    'namespace' => 'INBOX.',
    'maildomain' => 'xxx.com',
    'realm' => $DomainName,
    'preferred' => ''
);


I was able to successfully authenticate myself when using http://my-ip-
addr/horde/imp/test.php.

IMP Version
IMP: 3.2.1 
PHP Version
View phpinfo() screen 
PHP Version: 4.2.2 
PHP Major Version: 4.2 
PHP Minor Version: 2 
PHP Version Classification: release 
You are running a supported version of PHP.
PHP IMAP Support Test
server="localhost" user="prince" mailbox="{localhost:143/imap/notls}INBOX"
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