Strange behaviour with NC12 / Davdroid

Hi folks,

my NC12 seems to run relatively fine. But one issue remains. I can’t sync my phone with the cloud right now. Synching Thunderbird (through CardBook) works fine, though.

I set up DavDroid, it recognizes the addressbooks and calendars. When I sync now, no changes are being pushed from server to phone nor the other way.
I created a new account in DavDroid on my phone, but nothing synchs in or out there either.

Oddities: I can’t find anything in my /data/nextcloud.log newer than 2017-07-03 (July 3rd), which is strange. I’m not sure what other logs to check.

Any help much appreciated.

Might be related to this: