Keep getting the following error message on user CPU when attempting to send to group. Group was created on Outlook 2010 and is being used on Outlook 2003. Dont know if that may make a difference. The message could not be delivered because the recipient's destination email system is unknown or invalid. Please check the address and try again, or contact your system administrator to verify connectivity to the email system of the recipient.

Make sure the user picks the group from the address book rather than using a saved entry from the nickname cache.Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."

hi, any update? thanks,CastinLu TechNet Community Support