Owncloud 9 no calendars available

[Rocker]

Hello,

I installed Owncloud 9.0.2 with MariaDB and NginX on Ubuntu 16.04 in a virtual Machine (Server2012 R2)
For the installation i used this MANUAL and I did it exactly like described. (Except IP´s and the Domain)

On my cell phone´s I have the newest version of Davdroid (1.08)

To Sync calDAV and cardDAV with my Owncloud I use ClDav Synchroniser, and it works very fine.

So, but when I try to sync my Owncloud with Davdroid he tells me, he´s not able to find a calendar.

I tried following links in Davdroid (with internal and external address):

https:// 10.0.XX.XX/owncloud/remote.php/dav/
https:// 10.0.XX.XX /owncloud/remote.php/dav/principals/Bernd
https:// 10.0.XX.XX /owncloud/remote.php/dav/principals/
https:// 10.0.XX.XX /owncloud/remote.php/ 
https:// 10.0.XX.XX /owncloud/
https:// 10.0.XX.XX/owncloud/remote.php/dav/principals/users/Bernd/
https:// 10.0.XX.XX/owncloud/remote.php/dav/principals/users/
https:// 10.0.XX.XX/owncloud/remote.php/dav/principals/calendars/
https:// 10.0.XX.XX/owncloud/remote.php/dav/principals/calendars/Bernd

I also tried to disable the http2 in my configuration.
With and without präaptive autentification.
Different cell phones (all Android and newest version of Davdroid)

Attached a bug report from my cell phone.
0_1463835652372_davdroid-debug-2115608705.txt

Actually Davdroid works very well with my actually Owncloud 8.2.3 installation, described HERE

I would be very happy if we can solve this problem (This is the last point on my checklist to go live with my OC9 installation)

Regards Bernd

PS: sorry for my horrible English

[rfc2822]

According to the logs:

EXCEPTION java.io.IOException: stream was reset: REFUSED_STREAM

this is a duplicate of nginx HTTP/2 incompatible with okhttp. Please follow up there.