I had the same problem where I was able to enter my account in davdroid and Davdroid itself successfully found all my calendars, however none of them would sync with the phone’s calendar programs (both the native calendar and e-tar). Seems like a bug / change in android 7 broke calendar syncing. I was unable to get davdroid to work for months, however now that there’s a new DAVx5 client I decided to try it. They fixed it! The link is broken in the fdroid repo’s BTW, however I managed to install davx5 manually and everything’s working. So if anyone else has the same issue, give the new davx5 a shot!
DAVDroid starts Sync irregularly
It is expected that DAVDroid syncs every 24 hours and on local change
It seems DAVDroid has troubles determining whether there is an Internet connection and is not responsive to sync now.
What I discovered is that if you enter the Manage accounts menu and immediately exit, DAVDroid starts the sync.
DAVdroid does not determine whether there is an Internet connection. That’s all up to Android’s sync logic, which calls DAVdroid.
Did you have a look at FAQ: Why is synchronisation not triggered as set it in sync interval settings? Did you disable app standby for DAVdroid? Which Android version do you have? Which device do you have? Is there any additional information which could be useful for debugging?
Also, please provide steps to reproduce and debug info.