We have had this same problem with the IIS SMTP engine and Listserv,
particularly with Hotmail's notorious mail system. We worked around the
problem by changing the MAXBSMTP to 25. This has a similar effect as
using FULL822 option without breaking the headers.

We eventually stopped using the IIS SMTP engine because it kept running
out of threads due to the volume of mail from Listserv and switched to a
more robust mail relay.

andrew


>>> [log in to unmask] 3/21/2005 12:41:32 AM >>>
I appreciate your response.  I'll try the FULL822 option while 
researching options with Microsoft.  They've sent me a patch in the 
past, but the error has always returned - even in 2003's SMTP server. 

The error is documented here: