Click Next to attempt using an unencrypted connection.
- Use Outlook Web App to access mail in Exchange Online.
- Set up Outlook to access mail in Exchange Online through a Post Office Protocol (POP3) connection. For more info about how to do this, see Set up a POP3 or IMAP4 connection to your email in Outlook 2010 or Outlook 2013.
If Office 365 users who aren't F plan users get this error message, see the following Microsoft Knowledge Base article: