If you are setting up your new Office 365 accounts and require more than one to be set up on the same machine, you will most likely come across the below error message.
A workaround for this issue would be to set up your primary Exchange account first in Outlook, then set the remaining accounts up as IMAP accounts. Please note that the following tutorial is for customers running Windows 10, but instructions should be similar for Windows 7 and Windows 8/8.1.
1. Press the Windows key and start typing to search for "Control Panel".
2. Once in Control Panel, start typing "mail" in the top right (search bar). You will need to click on the "Mail" icon that appears.
3. In the "Mail Setup" window that appears, click "Email Accounts..."
4. Click "New"
5. Click "Manual setup or additional server types" and click "Next"
6. Select "POP or IMAP" and click "Next"
7. Enter the following details (your "user Name" is the full email address of the account you are setting up), and click "More Settings..."
8. Navigate to the "Outgoing Server" tab and tick "My outgoing server (SMTP) requires authentication", then click "Advanced"
9. Ensure the server ports and SSL settings match the following screenshot, then click "OK"
10. A connection test will begin. Once it succeeds, click "Close"
The account will now be set up in Outlook.
For any other Office 365 setup issues, please submit a support ticket to firstname.lastname@example.org, and our support team will be in contact with you.