need help for mailman configuration

[dinar ali kadri <dino pakishop com>]

Hi when i request to subscribe a list on mailman page after that i  
check my smtp-failure log i finds this error:

Jan 29 12:36:26 2005 (3959) SMTP session failure: 553, 5.3.0 <unix- 
bounces pakishop com>... user User unknown, msgid:  
<mailman 0 11482 547 unix pakishop com>

i want to know what to do coz in my aliases it is unix-bounces not  
unix-bounces pakishop com  my mailserver name is info.pakishop.com but  
i masquerade it in pakishop.com so then what is a mistake which i am  
making ?should i masquerade entire domain in my sendmail macros or  
shall i change something else ?

My http server name is www.pakishop.com so is it okay for giving  
mailman URL a virtual host name which is info.pakishop.com.


THanks