iCal no longer syncing with Google.

I am using Snow Leopard. Everything was fine and then poof. Error message reads: The calendar (https://google.com/calendar/etc. etc.) was not found on the server. Make sure the URL is correct." The URL is correct. I am given the options to Go Offline or Revert to Server.

I've checked my Google Calendar settings and iCal settings. What am I missing, folks?