550 not local host

[Thomas]

From one day to the other my Outlook 2002 has a problem
sending email to some recipients.
I get an error:

The following recipient(s) could not be reached:

'recipients_name' on 12/1/2003 5:53 PM
550 not local host 'recipients_domain', not a
gateway.

It happens to some contacts despite the fact that their
email address is correct. I have spent weeks trying to
fix this. My internet service provider told me after a
trouble ticket that the problem is local and has to do
with my Outlook. I have check "Authentication" and use
the correct port and smtp server. I deinstalled and
reinstalled Outlook - nothing seems to help.

Does anyone have an idea what to do?

Thanks

Thomas

 

[Jeff Stephenson [MSFT]]

Are you sure you're using the proper authentication for your ISP? This
problem is almost always one of not properly authenticating to your outgoing
server. If you trying different authentication mechanisms doesn't work,
could you turn on diagnostic logging (see
http://support.microsoft.com/default.aspx?scid=kb;en-us;Q300479) and post
the OPMLog.log file after you have this problem?