I can't drag and drop calendar events to different days, usually.

Hi,

I am a teacher and my organization uses Outlook calendars.  When I attempt to drag and drop events to different days of the week, I usually get a "cannot save event" message.   Even more strange, is that I can occasionally change the day.  However, I can always change the event to a different time on the same day.  Please let me know what I can do to fix this problem.  Thanks.

Cindy