What type of email account does he have? Does he get any NDRs back?

If IMAP account, it might be something this:
http://www.slipstick.com/problems/rr_ndr.asp
I'm not sure if this exact problem affects 2003, but it could be something
similar, especially if happens after he does something specific, like delete
junk mail.

--
Diane Poremsky [MVP - Outlook]
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Outlook & Exchange Solutions Center: http://www.slipstick.com/

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Poll: What version of Exchange server do you use?
http://forums.slipstick.com/showthread.php?t=33803

"Alberto" wrote in message
...
Dear ALL,

a customer of mine has a very strange behaviour with Outlook 2003.


Sometime, it seems to start sending a lot of email (from 100 up to 200)
but it really doesn't send anything, but it opens a lot of smtp
connections causing itself not responding no more.

Anyone of you could give me an idea?


Regards

Alberto
Brivio