Publishing Outlook calender to webdavserver with owncloud selfhosting schannel error

2

I am trying to publish my "Outlook 2013" calendar to my self-hosted owncloud 7.0.2 on a QNAP. owncloud is configured to accept only https.
I copy the link for the calendar from owncloud calendar site of my user and it looks something like this:

https://myserver:8081/owncloud/remote.php/caldav/calendars/myusername/mycalname

When I do this and try to publish from outlook I get an error message. I have to translate it because I don't have an english OS so the exact english message might look a bit different but it says:
Error uploading from "Calendar". Problem with the request.

I also see an error in the event viewer: EventID: 36888
Source: SChannel Message: severe warning was generated and sent to remote endpoint. This can lead to terminating the connection. The severe warning has the following TLS protocol defined code: 40. The windows SChannel error status is: 252

Does anyone know what this means and how to fix it?
I have searched the internet but it looks like no one had problems with publishing to owncloud.
I tried to disable the firewall (which one site mentioned to try). All other sites did not really have similar problems described.

Just as a side info: Outlook tries to connect. Pops up a warning because of the certificate and asks me if I want to proceed. After I confirm it pops up the logon credentials screen and I enter my credentials. Then it tries to upload for about 10 seconds and finishes with the described errors.

Any Ideas on how to debug are greatly welcome. Possibly with wireshark? Haven't ever used it though.

UPDATE:
To prevent confusion some more info:
I am not using an exchange server. My outlook is a local installation and saves all settings to a local PST file. I am using the function "publish online" -> "publish to webdav-server" on the calendars tab "start" menu.

Uwe Hafner

Posted 2014-12-15T20:56:20.847

Reputation: 133

What URL do you get when you publish your Outlook calendar? I get http://outlook.office365.com/owa/calendar/xxx/xxx/calendar.ics

– Sun – 2014-12-15T22:13:29.610

Well, I don't get an URL as it does not succeed. – Uwe Hafner – 2014-12-16T06:56:24.657

Yes. It is possible. There are numerous descriptions on the internet how people publish to google and owncloud. It just does not work for me and I don't know how to debug further to get more information on the problem or what I am doing wrong. – Uwe Hafner – 2014-12-16T08:02:01.987

I see that I provided some confusing information. I updated my question to clarify my setup. Thanks. – Uwe Hafner – 2014-12-16T08:11:01.250

as posted: outlook 2013 – Uwe Hafner – 2014-12-16T17:53:50.733

There seems to be opinions on the web that the public to webdav calendar does not work correctly. Perhaps you can try publishing to another provider as test. Run Process Monitor to see how Outlook behaves with a successful run. Then use Process Monitor to see where it fails with your server. Wireshark is good too, but I find it hard to decipher and use. Process Monitor is less verbose but it may give you some hints as to where to look. – Sun – 2014-12-16T18:58:19.507

No answers