Do you have selected the calendars to be synchronized in your DAVdroid account?
Can not edit shared calendars on owncloud anymore
Since the 9.1.1-1.2 -> 9.1.2-1.1 update of my owncloud server I can no longer edit calendars shared by other users with davdroid. I obviously first thought that this is a server issue and opened a issue in the owncloud bugtracker.
Now it turns out that the problem apparently depends on which entries are in the calendar and that only some clients (Davdroid and Evolution mail) have problems writing to calendars shared by others, whereas others (for example Thunderbird) work without problems.
I am uploading a Davdroid debug file 0_1480858544814_debug.txt and would like to ask you to tell me if this is definitely a server issue, and if so, if you have any idea what could be causing this.
Thank you very much for your help!
This is a duplicate of Updating existing / Uploading new record - EXCEPTION at.bitfire.dav4android.exception.NotFoundException: 404. As said there, this seems to be a server problem. DAVdroid uploads the iCal, and the server returns 404 Not Found. If there are any indications that this could be a DAVdroid problem, please post them in the referenced thread.
@rfc2822 Thank you and sorry for not finding the bug you mentioned myself.
I think you should check for the caldav-URL. Your debug-log shows the same problem like mine, so my solution could help you too