Switching Exchange 2013 over to a public accessible address requires a valid FQDN and a valid SSL Certificate. After installing the certificate on the server we need to find our way to the Exchange Administration Center. Once here do the following:
- Select Servers, then Certificates
- Choose the valid Certificate you plan to use and Click edit (double click seems to work also)
- Select the services to be used by the Certificate – SMTP, IMAP, POP, IIS
- After making your selection click Save
You will get a warning about the existence of the previous certificate, click Yes.
Now you should be able to test your Outlook Web App by going to the https:// address of your site