Your username is the actual name of the mailbox on the Exchange server. This name was set by your account administrator when your mailbox was created. It could be in the format of firstname.lastname, or name3, and is unique to your mailbox. For example, if your name is John Smith, your username could be john3 or john.smith.
Your primary email address (in our environment, this is also your User Principal Name, or UPN) is associated with your mailbox username. It will also appear in the From field of the messages others receive from your mailbox. You will be able to receive messages using other email addresses, but not send messages from them.
In order to log in to your Exchange mailbox, you need to either use your Exchange domain and username, or your primary email address.
You can find your primary email address either in CONTROL PANEL > Users, or in My Services > Email Addresses. Click the display name of the user. On the user settings page, the address is shown in Email Address (Login).
You can find your username and Exchange domain in CONTROL PANEL > Users:
- Click the display name of the user.
- On the user settings page, click the display name once again to see the username in the Edit User Info window.
You can also view the same information in My Services > Edit Profile under the Edit User Information section.