Hi, I'm new member here. I'm System Administrator in my company. One of my duties is maintain MS Exchange 5.5 SP4 email server which running on NT 4.0 SP6. My MS Exchange 5.5 SP4 server has some trouble since Dec-2003. If email address of the user contains 29 character, exp. msamosir@xxxxxxxxxxxxxxxxxxxx or rsiregar@xxxxxxxxxxxxxxxxxxxx can not receive email from outbound. And all my user can not receive email from outbound email address if contain 29 character too, exp. oshulinina@xxxxxxxxxxxxxxxxxx or hidayat_qadept@xxxxxxxxxxxxx For the solve this problem, I change my email address user with add or subtract the character, for exp. rsiregar@xxxxxxxxxxxxxxxxxxxx change to rlsiregar@xxxxxxxxxxxxxxxxxxxx, msamosir@xxxxxxxxxxxxxxxxxxxx to m.samosir@xxxxxxxxxxxxxxxxxxxx, and they can receive email from everywhere. The other problem is we can not suggest to our relation company to change their email address. Everything is OK before Dec 2003. Can anybody advice my problem? Is this a Bug of MS Exchange? Thank you in advance, Ramdan