coopfab wrote:

One of our clients cannot receive any emails that are sent from any
workstation on our Windows 2003 Server network. We can send and they
can receive emails if we use our ISP webmail portal though. The only
thing our client will tell us is that our email is changing,
preventing our emails from getting through, and that the problem is
with the host. This makes no sense, but the fact remains that they
don't get our emails, even if we reply to one of their incoming
emails. What is more baffling is that this just started a week ago
with no changes made to our own network.

When you attempt to send a message to this recipient, what happens? Do the
messages appear to send and move to the Sent Items folder? What type of
account are you using? What is the sending format? What version of
Outlook? Is this recipient in your Contacts? If so, what do the Properties
of the e-mail address say is the Internet format?
--
Brian Tillman [MVP-Outlook]