1. Open Outlook.
2. Select Tools > Accounts. The Internet Accounts dialog box will appear.
3. Click the Mail tab.
4. Click Properties.
5. In the Properties window, click the Advanced tab.
6. For the Incoming mail (IMAP) server, check the box labeled This server requires a secure connection (SSL).
7. The Incoming Mail (IMAP) box should read 993.
8. Click OK.