Have set up quite a number of iphones for exchange access I was surprised when a client for whom I had configured about a dozen and trained their junior sysadmin how to update the iphones – transfer apps – and add Exchange accounts for their users called to say one stubborn Iphone just would not work. First thing I checked was access to the users mail via OWA on an Exchange 2007 server. Working fine.
I noted that the iphone has a slightly out of date IOS version so got that update as part of the check but still nothing. The usual – account name or password incorrect !!
Finally got the user to test the credentials for their own Iphone and it worked. So the next thing was to check the users details on the SBS 2008 server and noted that the users logon name was not the company standard of firstname.surname rather it was firstnamesurname with no dot. Got the user then to check using this username and the correct password and they were able to login and collect mail on the iphone.
So the moral is OWA will accept the username in either form (the firstname.surname and firstnamesurname with no dot) but the server will only verifiy the iphone exchange account if the correct logon name is used.