The most basic aspect of administering any messaging-and-collaboration system is configuring the vast and varied settings that relate to recipients. First, the user account must be mailbox enabled, which means you need to create a mailbox on the mailbox database for the user account. To do this, you need to use the Enable-Mailbox cmdlet. This command appears here:
Enable-Mailbox -Identity nwtraders\MyNewUser -Database "mailbox database"
When this command runs, you will get a prompt back that appears as follows. It tells you the name of the user account, the alias assigned, the server name on which the mailbox database resides, and any quota restrictions applied to the account.
Name Alias ServerName ProhibitSendQuota ...