ITS HAS BLOCKED IMAP ON AUGUST 4, 2020. THIS ARTICLE IS HERE MERELY FOR HISTORICAL PURPOSES

Email addresses that have been converted from stand-alone addresses to shared mailboxes cannot be configured like regular mailboxes to Outlook for iOS. They must be configured via IMAP.

1. Open Outlook and tap the menu icon.
2. Tap the settings icon.
3. Under Accounts, tap Add Account.
4. Tap Add Email Account.
5. Enter the email address of the shared mailbox and tap Add Account.
6. You will be taken to the Weblogin page. Tap Not Office 365 in the top right corner.
7. Tap on Change Account Provider in the menu that appears
8. In the next screen, choose IMAP.
9. In the next screen fill in the following after selecting Use Advanced Settings: 
   Email address: the address for the shared mailbox
   Display Name: the name of the shared mailbox
   
   Under IMAP Incoming Mail Server
   IMAP Host Name: outlook.office365.com:993
   IMAP Username: enter the email address of the account that has access to the shared mailbox, followed by a "\" and then the email address of the shared mailbox itself (e.g. yourname@austin.utexas.edu\shared.mailbox@austin.utexas.edu)
   IMAP Password: Enter the password of the mailbox with the permission to access the shared mailbox
   
   Under SMTP Outgoing Mail Server
   SMTP Hostname: smtp.office365.com:587
   SMTP Username: Enter the email address of the mailbox with the permission to the shared mailbox (e.g. yourname@austin.utexas.edu email address)
   SMTP Password: Enter the password of the mailbox with the permission to access the shared mailbox