Outlook 2003 will not connect to Exchange 2007 via RPC while Outlook 2007 will

We have a new Exchange 2007 server running on Server 2003 R2 X64 SP2. The server is configured with a SAN cert. OWA works fine. An Outlook 2007 client configured to connect via HTTP works fine both internally and externally--no problems at all.

Went to setup a couple of older Outlook 2003 clients and had trouble. It is configured to connect via RPC over HTTP, it works internally, but externally yields the following error:

"The connection to Microsoft Exchange Server is unavailable. Outlook must be online or connected to complete this action"

Looking for any insight.
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bcphilcoConnect With a Mentor Author Commented:
Ultimately, we had to uninstall RPC over HTTP, then reinstall. Everything works now.
Here you go,

I would start with this:


Also and if that does not work go through the whole post, it has several methods:


bcphilcoAuthor Commented:
Thanks for the recommendation. I went through the postings but found they all addressed problems with Outlook 2007 with Exchange 2003. Our problem is with Outlook 2003 to Exchange 2007. Again, Outlook 2007 clients work just fine; can't get Outlook 2003 to work.
In that case check out:

"Outlook 2003 will not connect to Exchange 2007"


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