Method 1: Create a new alias for the user in Office 365Create a new alias for the user in Office 365, and use it to set up Outlook. To do this, follow these steps:
- Sign in to the Exchange admin center.
- Click recipients, click mailboxes, and then double-click the user's mailbox.
- Click email address, click Add (), select SMTP, and then add a new alias that uses the .onmicrosoft.com domain. For example, add the firstname.lastname@example.org alias.
- Use the alias that you created in step 3 instead of the user's email address to set up Outlook. When you're prompted again to enter credentials during the setup process, use the user's actual Office 365 email address.
Method 2: Change the user name or passwordChange the user name or password of the user's Office 365 account or of the user's third-party account so that it is unique for the user's Office 365 account.
Article ID: 2976203 - Last Review: 29 Dec 2016 - Revision: 1