I can’t reproduce the problem with OwnCloud 7. I guess it’s either server misconfiguration that prevents REPORT on this URL or an old OwnCloud version with problems.
@vacy @apeiron Is it possible that your server forbids REPORT on calendar URLs?
@apeiron Which server software do you use?
Please provide steps to reproduce and information about your server software.
Other apps like Thunderbird still sync without issue, so I know that it’s specific to davdroid.
Maybe Thunderbird doesn’t use REPORT or it didn’t try to fetch more than one event but DAVdroid did, so the REPORT issue just didn’t arise with Thunderbird yet.