HTTP/1.1 403 Forbidden
Date: Dow, 01 Jan 2000 00:00:00 GMT
Content-Length: 148
Content-Type: text/xml; charset="utf-8"

<?xml version="1.0" encoding="utf-8" ?>
<error xmlns="DAV:">
  <supported-format/>This server currently only supports text/calendar format.
</error>