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enty46

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Why won't Outlook 2003 log onto POP3 site?

553 sorry, that domain isn't in my list of allowed rcpthosts (#5.7.1)

This is the error message I get when trying to send message from newly configured Outlooks 2003 POP3 profile.  Can send successfully to any email address in the domain of the host machine but cannot send to any email address at any other domain.  Always get this message.  Never had this problem before.  Why is this happening and how to fix?

Running XP Pro
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Are there any spam firewalls in place, or IP address restrictions on the POP3 server.

Is this through an ISP?  Where does the mail server reside?
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enty46

ASKER

The mail server resides with Network Solutions.  There has never before been a problem with this mail server, and, indeed, I have just discovered that mail from the dmoain in question can be sent successfully via a dial-up connection.  Our primary broadband connection is over HughesNet satellite, so it appears to me to be a gateway issue.  But mail on other domains goes out fine over Hughes, and so has mail from the domain in question until just today.  Right now, I'm still wondering what the error message means?
I've read a few places it can be a deceptive message.  It could be a relay access denied message.

HughesNet may be blocking port 25 for anti-spam purposes.  I've had my provider block port 25 in 1 location and the other 13 locations were just fine, so it may be the subnet they have you on.

Have you tried to telnet to your mail server?

i.e. telnet mail.company.com 25
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Well, what I've discovered is that Outlook 2003 installs with pre-configured default settings that are based on key assumptions.  One is that smtp will use port 25 and another is that outgoing mail server authentication is not required.

It turns out that  changing the smtp port from the default 25 to to 587 and selecting outgoing mail authentication solves the problem I'd been having.  This does not explain why smtp functioned ok earlier using a dial-up connection but would not work on broadband.  But changing the port to 587 and authenticating the user clearly made a difference, as now I am able to send messages over the HughesNet broadband connection.  Interestingly, other mail domains we use do not require this configuration change.  Evidently Microsoft's default configuration for Outlook 2003 works with some mail servers and not with others.  I am using a mail server owned by Network Solutions.

In light of that, it sounds as if indeed, they are blocking port 25 on that particular subnet.
On their dial-up, they are not blocking it.

HughesNet most likely has a opt-out option for port 25 in which you either call them up and opt-out of them blocking port 25 or they may even have a website page that allows you to opt-out.

You may want to go that route to, to keep things standardized at all locations, instead of having to remember that port 587 is the port.
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enty46

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