@cookyr: Thank you for your reply, but I am still unable to connect to the server. Instead of one "default calendar" I have multiple calendars stored on the server.
I tried both accessible URLs to no avail:


Rainlender recognize "default calendar" as <calendar name>, but offers only an empty drop down list for the calendar names. The actual name of the calendars on the server are recognized and I receive the "url does not contain any calendars" error.
Using any arbitrary string as <calendar name> and ending the whole URL with "/default calendar" will also trigger the empty drop down list.

Can you run Rainlendar in the debug mode and send the debug log to me (use the Rainlendar's support address and include a link to this post)? I can check from the log what exactly the server is replying to Rainlendar when it tries to read the calendars.

According to the logs the server sends a "417 - Expectation Failed" response. A short trip to google reveals that this is a known lighttpd bug that won't be fixed in the stable 1.4 branch redmine.lighttpd.net/issues/377

Time to try a new http server I guess ...

There is a workaround for the lighttpd issue in Rainlendar but unfortunately it's only for the network shared calendar and not in CalDAV plugin. I can add the same implementation to CalDAV too in the next version.

The workaround is to set the "dontSendContinue=0" in Rainlendar's settings file to "dontSendContinue=1" which will remove the "Expect:" header from the request.

I switched to apache, now everything works as expected.

My Rainlendar config file does not have a "dontSendContinue" option, in which category should this option be added if one would continue to use lighttpd?

The setting is currently shown only under the "Network Shared Calendar" section if there are any calendars with that type.