1. Open Windows Mail.
  2. Click the Tools menu, and select Accounts…
  3. Click Add…
  4. Select Email Account, and click Next.
  5. Enter your name as you would like it to appear in the ‘From:’ field of outgoing messages (e.g., Joe User), and click Next.
  6. Enter your full email address including your domain name (joe@example.com).
  7. Fill in all necessary fields to include the following information:
    Incoming mail server type: POP3
    Incoming mail (POP3 or IMAP) server: mail.mainstreamit.com
    Outgoing e-mail server (SMTP) name: mail.mainstreamit.com
    Outgoing server requires authentication: (checked)
  8. Click Next, and enter your full email address including your domain name (joe@example.com) and your email password.
  9. Click Next, and then check the box next to Do not download my e-mail at this time. Click Finish.
  10. On the Internet Accounts screen, make sure that your mail.mainstreamit.com mail account is selected, and click the Properties button.
  11. On the Advanced tab, enter 465 in the in the box next to Outgoing mail (SMTP), and check the box next to This server requires an encrypted connection (SSL).
  12. Check the box next to This server requires an encrypted connection (SSL) under Incoming mail (POP3). The box next to Incoming mail (POP3) should automatically update to 995.
  13. Click OK. You’re done! Close the Internet Accounts window and click Send/Receive to start checking your messages.