To add your mailbox in recent versions of Outlook including 2013 and higher, please follow these instructions:

Autodiscovery

If your domain is set up for autodiscovery:

  1. In Outlook, click File.
  2. Click Add Account.
  3. Enter your name, email address and password. Click Next and then click Finish.

Manual Setup

  1. In Outlook, click File.
  2. Click Add Account.
  3. Select the Manual Setup radio button and click Next.
  4. Select the Pop3 or IMAP radio button and click Next.
  5. Enter your name and email address.
  6. Select IMAP account type.
  7. Enter secure.greatmail.com for both the incoming and outgoing mail server fields.
  8. Under Logon Information, enter your full email address for the User Name field.
  9. Enter your password.
  10. Click More Settings.
  11. Click the Outgoing Server tab and check the box next to My outgoing server (SMTP) requires authentication.
  12. Click the Advanced tab.
  13. Under Server Port Numbers, select SSL encryption type for the incoming server.
  14. Make sure the incoming server port number is 993.
  15. Select STARTTLS encryption type for the outgoing server. If STARTTLS is not an option, select TLS encryption.
  16. Enter 2500 for the outgoing server port number.
  17. Under Folders, enter INBOX in the Root folder path field.
  18. Click OK.
  19. Click Next.
  20. Click Finish.