On Dec 21, 1999 11:47am, ROBERT ULRICH wrote to ALL:

 RU> I have a user who when they send a message to one individual gets the
 RU> error message:

 RU> "Error adding message to J---- S-------:  Duplicate Message [536870941]
 RU> 0 Messages accepted for delivery"

 RU> What has this person done, and more importantly how can he fix it?

What has he done?  Exactly what the System Reported back:

                    "Duplicate Message"

He attempted to send a MESSAGE that was already sent.  WINSERVER is
extremely tight on this and is 100% accurate in this regard. In other
words, if the SYSTEM says it is a DUPLICATE, then it is 100% truly a
duplicate message attempted to be added into the system.  You can't
have 2 exact messages in the same conference with 1 exception: FIDONET
netmail conferences.  Fidonet Netmail Conferences is he only
conference type, where duplicates are allowed.

The only fix is to "Change some part" of the message, from, to, subject,
date or the message body, or even a different conference.
--- Platinum Xpress/Win/WINServer v3.1