I am having some issues getting new desktops to connect to our existing Exchange 2007 server. When the user logs in to the domain and I launch Outlook 2007 the connection information is automatically filled in as it should. When Outlook trys to connect to the server I continually get a box popping up asking for a username / password combination. Nothing we enter in this box seems to be accepted by the server. These are all new Windows XP SP3 machines running Office 2007 Small Business Edition. Outlook is connecting via MAPI and Outlook Anywhere has been disabled.Network Background:1 DC Running Server 2003 R2 SP2This server runs DNS and WINS1 Exchange 2007 Server on Server 2003 R2 x64 SP2This server is also the DHCP ServerThings we have verified:Kerberos is running correctlyAutodiscover directory in IIS is set to integrated authenticationThe only thing to my knowledge that has been modified on the Exchange box since the last client successfully connected is the 1 year security certificate generated by the setup process expired and was regenerated using the Exchange Shell. Also note all other clients that were already configured still connect fine.Any suggestions would be much appreciated as we have not found any solutions to this anywhere.