I have been using DAVdroid since Mar 7. In that time, it has stopped syncing twice now. Just now, it stopped syncing 2 days ago and says “Sync is currently experiencing problems. It will be back shortly.”
It does not come back (shortly or otherwise). I have tried forcing a sync, disable/re-enable sync, and rebooting the phone. It will not update.
Checking with a co-worked with the same issue, he said that he “just deleted the account and re-set it up.” I tried that last time and it worked.
Right now, it is hung. I will hold it that way for a day or two more, if you want to collect any information.