What have you tried? How far does it get before there is a problem (eg does it create the email but not send it?)
Are you using the Outlook client to send email, or have you configured the email router?
Are these emails being created and sent by workflows? Who are the emails sent "from"? Does the user who owns the workflow have "Send on behalf of other users" privilege?
Hope this helps.
Adam Vero, Microsoft Certified Trainer | Microsoft Community Contributor 2011
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