Small auto-reminder post for the future: How to configure a Microsoft Exchange mail account in Outlook to work with RPC over HTTP (which means, to access your exchange account from outside your office).
- Close Outlook and go to Control Panel → Mail
- Email Accounts → Choose your Exchange account → Change

- More Settings → Check the Security tab

- Connection tab → Check Connect to Microsoft Exchange using HTTP

- Click the Exchange Proxy Settings button

- Write your proxy server url, check your desired options of HTTP-TCP/IP preferences, and select Basic Authentication.
- Save all, and close.
Done :)