exchange calendar not showing up

Hello,

since last Sunday I started seeing problems with my work Exchange calendar in iCal (OS X 10.8.4). A newly created event in iCal would not be correctly created and invitations were not being sent out. I also found that event was not synced, so not visible in Outlook or Outlook web app.

So I decided to delete the calendar in iCal and recreated. The issue is that does not longer appear in the iCal list. There is the Exchange section, but none calendar below. See attached screenshot.

I reset iCal by erasing all the iCal prefs and caches (~/Library/Calendars, ~/Library/Preferences/com.apple.iCal.plist, ~/Library/Caches/com.apple.iCal) recreated the Exchange account, but still the same problem.

This is really weird and I could not finding something useful searching on the web. Anyone ever seen something like this?

Thanks.

Davide