If org-caldav reports a problem with the given URL, please triple-check that the URL is correct. It must point to a valid calendar on your CalDAV server.
If the error is that the URL does not seem to accept DAV requests, you can additionally check with ’curl’ by doing
curl -D - -X OPTIONS --basic -u mylogin:mypassword URL
The output of this command must contain a ’DAV’ header like this:
DAV: 1, 3, extended-mkcol, access-control, ... etc. ...
By default, org-caldav will put all kinds of debug output into the
buffer *org-caldav-debug*. Look there if you’re getting sync errors
or if something plain doesn’t work. If you’re using an authinfo file
and authentication doesn’t work, set auth-info-debug to t and look in
the *Messages* buffer. When you report a bug, please try to post the
relevant portion of the *org-caldav-debug* buffer since it might be
helpful to see what’s going wrong. If Emacs throws an error, do
M-x toggle-debug-on-error
and try to replicate the error to get a backtrace.
You can also turn on excessive debugging by setting the variable
org-caldav-debug-level to 2. This will also output the contents of
the events into the debug buffer. If you send such a buffer in a bug
report, please make very sure you have removed personal information
from those events.