Why does my Exchange account work on my iPhone, but not Mail.app?

Solution 1:

Most likely because your corporate exchange server is running Microsoft Exchange Server 2003. Snow Leopard now only connects to Exchange 2007 (See http://www.apple.com/macosx/exchange/) whereas Leopard used to connect to Exchange 2003 using the OWA mechanism.

iPhone supports both Exchange 2003, 2007 and 2010 it seems (See iPhone User Guide , page 2);

Solution 2:

I'd been struggling with the same issue for over a year. Finally I installed DavMail Gateway which is free.

It provides support for Exchange 2003 ( using OWA ). Using it you can even get support for LDAP directory services & even events in iCal!!

See page for details. Step-by-step instructions on:

Setting up DavMail on OS X

IMAP Mail setup

Solution 3:

Have you tried everything listed in this Apple doc?

Solution 4:

I've been having this problem with Exchange Server 2003 and Mail under Snow Leopard, and it's because the IMAP process on the server periodically dies. This affects the Mail app on the computer and not the iPhone because, as another answer here mentions, the iPhone uses ActiveSync, while the Mail app on the computer relies on IMAP if it's not Exchange 2007 or newer. Someone needs to log into the server and restart it.

One possible fix is here.