I'm getting this error message over and over when ical is on:The URL https://caldav.calendar.yahoo.com/principals/users@sbcglobal.net/ encountered HTTP error 404. Make sure the URL is correct.

Same exact problem: all apple devices. 😟

anyone have the fix? has yahoo or AT&T confirmed? Or just sbcglobal.net users?

I have been having this problem for the last week. I went to iCal: Preferences: Accounts and checked what accounts were enabled. I had 3 accounts listed (mobile me, icloud and yahoo), and the icloud and yahoo were enabled. I unchecked the enable for the yahoo account, and haven't had the error message since then.

by unchecking means the yahoo calendar will no longer display. That isn't quite a fix if you happen to use yahoo calendar as your default.

I have the exact samet thing happening on my iMac. Have they figured it out yet??

Thanks. This solved my problem. (But i don't use Yahoo or ATT calendar so I did not need iCal to sync with either of them)

I encountered the 404 also in iCal last few weeks which either means they changed servers or there is some other sign on problem. Today I just removed the Yahoo Caldav completely and re-entered ...and using the auto function I got a message that the server was not secure and my calendar could be seen by others....so I then tried the manual option and that could not locate a server for my email address which is .......@sbcglobal.net and got the message that a server could not be located for sbcglobal.

Up til a few weeks ago or so sync worked fine with iCal. I had called ATT ....and the agent said he wasn't familiar with Apple software......I swear that there was a point where the sync worked for awhile....but since I don't have other iOs devices to sync with I decided the heck with it.

Looking at other discussions I see the problem goes back to Oct 2012 and others have had conversations with Yahoo and said that Yahoo has engineering problems and they were working on it. I also have recently encountered sign on problems with iMail with pop up that repeatedly requires my password to Yahoo as well. But this is intermittant and probably the imap mail server is overloaded. Someone else suggested using a short (8 character) password...that that may be the problem.

I was just thinking of going to Google Mail and changing my e mail but that would be a pain. Also ATT is supposed to be changing e mail in June ..I read and also going to new designations for POP3 server(s)