Hi all, I want to upgrade Exchange 5.5 to Exchange 2K , everything is ok except that I can't receive email from internet. I receive this error : unable to relay test@xxxxxxx My server specification is : Windows NT 4.0 (PDC), Exchange 5.5 , SP4.0 and I use In-Place method for upgrade process. The exchange site name is xxx.com and when I want to upgrade it , I have to change the site name and delete the invalid character.So I just change the site display name to xxxcom and internal site name is still xxx.com. I think that the main problem is changing my site name because when I install a fresh exchange 2K with the same settings everything is ok and I can receive email from internet. I use this document : In-Place Upgrade from Microsoft Exchange 5.5 to Microsoft Exchange 2000 White Paper as a reference. Any help will be appreciated. __________________________________________________ Do you Yahoo!? Yahoo! Tax Center - forms, calculators, tips, more http://taxes.yahoo.com/ ===================== Use the below link for Archives, and to set your preferences. http://thethin.net/exchangelist.cfm