In your Control Panel
Click on the name of your Hosting Plan (typically Exchange Hosting, SharePoint Hosting, etc)
Click Hosted Organizations

Click your Domain Name

Click Distribution List

Click Create New Distribution List

Enter your Display Name for the new distribution list

Enter your Email Address for the new distribution list

Click Create Distribution List

Click on the Add button to add any Mailboxes, Contacts, or other Distribution Lists that should receive email at this address

Click Save Changes

Go to the Mail Flow Settings Tab

Uncheck ‘Require that all Senders are Authenticated’

Click Save Changes