Outlook 2003 pop3 account failures??

[WetBehindEars]

I have an XP workstation with Outlook 2003 installed. The user can send mail
and reply to mail, but when a user replys back it fails. The user gets a
failure notice. Any suggestions why they cant receive replied messages??

 

[Brian Tillman]

I have an XP workstation with Outlook 2003 installed. The user can
send mail and reply to mail, but when a user replys back it fails.
The user gets a failure notice. Any suggestions why they cant
receive replied messages??

And the exact failure message is?

 

[WetBehindEars]

This is an automatically generated Delivery Status Notification.

Delivery to the following recipients failed.

The user is using Outlook 2003 w/ pop3 account. User on XP Home.
They can receive regular mail and mail thats been forwarded to them, but not
messages where people have replied to them.

 

[Brian Tillman]

This is an automatically generated Delivery Status Notification.

Delivery to the following recipients failed.

There should be more to it than that.

The user is using Outlook 2003 w/ pop3 account. User on XP Home.
They can receive regular mail and mail thats been forwarded to them,
but not messages where people have replied to them.

Sorry, I don't understand this sentence. Which "people" and replied to
whom?