Error 415

Hi,
I'm a maintainer from the project invis-server.org. We try to integrade vdirsyncer in our server-system to synchronize Kopano Calendars with other CalDAV servers.

Similar to this issue "https://github.com/pimutils/vdirsyncer/issues/502", we get the following error while synchronize from kopano to owncloud:

"415 Client Error: Unsupported Media Type for url"

In my opinion the reason for this error is, that the exported ics-files from kopano contains DOS-linebreaks.

• vdirsyncer version: 16.0 (shipped with openSUSE leap 15.0)
• If applicable, which server software (and which version) you're using
• Python 3.6.5
• openSUSE Leap 15.0

[general]
status_path = "~/.vdirsyncer/status/"

[pair my_calendars]
a = "my_calendars_local"
b = "my_calendars_remote"
collections = [["kalender", "kalender", "personal"]]

[storage my_calendars_local]
type = "caldav"
url = "https://mail.kassandra-net.loc:8443/caldav/stefan/kalender"
verify = "/etc/invis/certs/ca.crt"
username = "stefan"
password = "********"

[storage my_calendars_remote]
type = "caldav"

We can simplify this URL here as well. In theory it shouldn't matter.

url = "https://oc.xxxxxx.de/remote.php/caldav"
username = "stefan"
password = "**********"

error.log

Start with the linked error.log and the supplied CalDAV configuration, then compare the failure with issue 502. Reproduce the Kopano-to-ownCloud synchronization using the reported vdirsyncer, Python, and openSUSE versions; the work is done when the 415 response is explained and the synchronization behavior or required configuration is clearly resolved.