Brian Gaff presented the following explanation :
So what have you got set up to send and what is the error message?

The message I mentioned.

Outlook
could be very about the content of forwarded messages and these days I tend
to cut and paste only the stuff I need and start a new clean message after
deleting the old one from the outbox.

As said, there is nothing in my Outbox, it is completely empty.

I'm assuming that most flavours of
Microsoft email have the same problem as I saw it on OutlookExpress yesterday
Don't you think 97 is a little old now?

No, it normally works very well indeed, updating only adds more bells
and whistles.

I don't even recall if it could
manage the server port changes demanded these days.

It does..