Kolab 3.2: I can not send/receive any e-mails

[Penguin Power]

Hi,

It would be great if any of you can help me to fix this problem.
I could successfully install kolab 3.2 on centos 6.
Address book, calender works great and even Activesync was just awesome 
with my android devices. However, it is strange that I can not send or 
receive any e-mail....
Since kolab is working with postfix and cyrus imap.. I don't know where 
to start.
I tested postfix using telnet and it could send e-mail w/o any error 
message but the recipient could not able to receive the e-mail.
I don't know where the mail box located. It seems kolab is not storing 
e-mail in POSIX home directory.
cyrus imap seemed broken. I don't know where to start.
Thank you for your precious time.
P.S. I have read all the document on kolab.org website. and I am stuck...