I changed my account password. Was taken to a screen that said "The following websites and applications have been removed from your App and Website Connections list when you changed your password. To re-establish the access, go to the site and grant permissions again: CalDav Project - Zimbra"
How do I re-establish "CalDav Project - Zimbra" access?
From my own caldav debugging, it looks like the homset-url no longer lists anything in the resources collection