Scheduling and managing events using Outlook.com calendar
This started happening to me during January, and after reading this thread and a bit of experimentation, it seems that some idiot at Microsoft has decided to use the NAME of the calendar entry as some form of index.
If I create any event with the same name as another event (including using the usually helpful 'Duplicate Event' option) the event is created, but then can't be edited - giving the same 'can't save' or 'something went wrong' modern/useless error message.
If I create a new event with a slightly different name (I've just started adding (1), (2), etc. to the end of all my regular events :| ) it seems to work.
If others could give that a try and see what they think, it might help Microsoft's obviously incompetent developers get somewhere with this...