Pls. Help - Some Lost Mail......

Hi Suser's Please help me how can i monitor our incoming/outgoing mails. We are encoutering some lost mails frequently. There are instances that the recipient is directly addressed by the sender but he/she did not receive anything but the addresses specified in the cc receives the mail loud and clear. The sender decided to faxed his email to us coz its important. We've checked the email address its correct and tried test his/her email address he/she can received. We also noticed so many files from mqueue. Can we delete the contents? What is the effect? Thanks and regards -------------------------- Jonathan J. Terbio -------------------------- P.S. Waiting for Suse 7.1a/7.1 here in the Phils. :-)