@rfc2822 Thanks for taking your time.
Tasks only caldav doesn’t sync
I created a tasks list in nextcloud application but it doesn’t appear in davdroid after sync.
I don’t have problem with a classic calendar with task list.
You need to install Open Tasks to be able to see tasks on your Android phone. Please be sure to install Open Tasks before installing DAVdroid. You may need to uninstall DAVdroid, install Open Tasks and install DAVdroid again.
Ok, forget my question, that works fine when I sync caldav only.