Hello,
This error generally means that the SMTP server is not configured to accept connections from the PopGrabber machine (either because it is blocking the IP or because the SMTP server is not enabled on this port). Some good information regarding Exchange 2007 SMTP configuration can be found at:
http://msexchangeteam.com/archive/2006/11/17/431555.aspxTo receive messages forwarded by PopGrabber, make sure that the SMTP connector allows anonymous connections to deliver emails to the local users.
For more information about the settings required for this look at this post:
http://forum.eclarsys.com/index.php/topic,60.0.htmlLet us know if this works for you.
Regards,
Eclarsys Support