I use Mountain Lion on my new iMac. Every time I open iCal I get the following message: The server responded with an error. The URL https://email@example.comfirstname.lastname@example.org/user/ encountered HTTP error 404. Make sure the URL is correct. I'd love some help. Thanks.
The url looks wrong in that calendar is not spelled correctly.
Have you tried the following:
Retrieving data ...