I’m running the CardDAV server locally, with no internet access, on a Synology NAS. The phone and account have no trouble connecting, no error syncing. It all worked seamlessly on Android 7, but just stopped working on Android 8. I have deleted the app and reinstalled (apk from f-droid) multiple times. I also got the newest version from Google Play (2.4), but that doesn’t help either. I also reset the contacts app many times as well. Attaching the debug file, since the verbose logging doesn’t work for me (Whenever I push “Send log” and select the appropriate method, it never sends or saves). I have also noticed, that if I tried to create a new address book, it always comes back as “HTTP 403 Forbidden”, though everything works on other phones and the earlier mentioned android version.