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Dear Experts,<br />
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I am having a hard time getting an external user to send e-mail to a distribution group internally. &nbsp;I created a contact for him in my domain with his eternal e-mail and added him to the distribution group. &nbsp;However, every time he sent an e-mail to the group, he got bounced back with undeliverable. &nbsp;Exchange 2010 / 2008 DC / Outlook 2016. &nbsp;Thanks.
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Dear Experts,

I am having a hard time getting an external user to send e-mail to a distribution group internally.  I created a contact for him in my domain with his eternal e-mail and added him to the distribution group.  However, every time he sent an e-mail to the group, he got bounced back with undeliverable.  Exchange 2010 / 2008 DC / Outlook 2016.  Thanks.

External E-mail as Contact Sending E-mail to Internal Distribution Group

Exchange is the server side of a collaborative application product that is part of the Microsoft Server infrastructure. Exchange's major features include email, calendaring, contacts and tasks, support for mobile and web-based access to information, and support for data storage.

Exchange

Microsoft Outlook is a personal information manager from Microsoft, available as a part of the Microsoft Office suite. Although often used mainly as an email application, it also includes a calendar, task manager, contact manager, note-taker, journal, and web browser.