I have WinXP Pro SP2 and MS Office 2003 (upated to SP2) Standard edition and
am using MS Outlook 2003.

When I send/receive messages, I get this message:

Task 'xxx- Sending' reported error (0x80042109) : 'Outlook is unable to
connect to your outgoing (SMTP) e-mail server. If
you continue to receive this message, contact your server administrator or
Internet service provider (ISP).'

My MS Outlook 2003 settings:
POP3 = 110
SMTP = 25
Server names are correct. I can ping server with no lost packets.

My MS Outlook worked well before even with my antivirus (NOD32) and Windows
Firewall enabled. However, for the sake of ruling out that any of these two
could be responsible, I turned both of them off. I still got the same MS
Outlook error message.

I'm behind a USR8054 router but the router is NOT set to block ports 110 and
25.

Help, please!

Interestingly, sending e-mails using Outlook Express(same server names and
port numbers as in MS Outlook 2003) works just fine.

So, it has nothing to do with my isp, firewalls, routers, or antivirus
programs.

What didn't work:
- deleting and re-building e-mail accounts

What worked for me:
- uninstalling/rebooting/installing Outlook (most probably wouldn't have
needed to do this if I tested the pst files first)
- scanpst.exe detected errors in a couple of data files I was using (I have
6)
- simply repairing errors with scanpst.exe wasn't sufficient (i.e., using
the old outlook.pst resulted in experiencing the same problem so I exported
the data from the old outlook.pst)
- created new profile and new outlook.pst; then imported old data into them;
didn't have to export data from my other pst files

I wish MSOutlook provides more detailed error messages than just "...cannot
connect to incoming/outgoing e-mail server..." It's pretty useless
information when one finds out in the end that the problem is either with MS
Outlook itself or one/several of the pst files. It's exceedingly
inconvenient as well when one considers that the error message is very
misleading resulting in the user wasting a lot of time testing a lot of
things (ISP, firewalls, antivirus, etc.) that need not have been tested in
the first place. It's very time consuming because "check your firewall" and
"check your antivirus" seem to be the standard answers that you get from
ISPs and from message boards. In all the problems I've had this year with
MS applications, my firewall and antivirus have never turned out to be the
problems. I can't say the same for my router, though, but this only applies
to the tweaking I will have to do to make my home compu accessible via RDC.

Matty wrote:

- created new profile and new outlook.pst; then imported old data
into them; didn't have to export data from my other pst files

Avoid importing from a PST. You lose data and it's always unnecessary.

I wish MSOutlook provides more detailed error messages than just
"...cannot connect to incoming/outgoing e-mail server..."

The transport logs usually contain better diagnostic information.
http://support.microsoft.com/kb/831053/en-us
--
Brian Tillman [MVP-Outlook]