When setting up a new Outlook profile (in 2010 & 2013, at least), sometimes you’ll see this error:
The action cannot be completed. The Connection to Microsoft Exchange is unavailable. Outlook must be online or connected to complete this action.
This is almost never because Exchange is unavailable or because Outlook is offline. The problem is because something has gone wrong with the Autodiscover process or…who knows what. In any case, one of two things will fix this problem almost every time.
1. Bypass Autodiscover by using the manual setup process. Be sure to configure the Exchange proxy settings.
2. Set up the Mail profile with caching turned off. Once it’s connected to Exchange, turn caching back on.