Thanks for your report.
This has been fixed with version 1.0.1.
Adding my fastmail account works. Caldav is syncing probably, carddav not. This happens when I generate an app password for mail, carddav, caldav and also when I generate one for the use of cardfav alone. Thanks for the help!
java.lang.SecurityException: Permission Denial: writing com.android.providers.contacts.ContactsProvider2 uri content://com.android.contacts/raw_contacts?account_name=Fastmail&account_type=bitfire.at.davdroid&caller_is_syncadapter=true from pid=13535, uid=10116 requires android.permission.WRITE_CONTACTS, or grantUriPermission()
DAVdroid doesn’t have the permission to write contacts. Please allow the permissions in DAVdroid, and see https://davdroid.bitfire.at/faq/entry/miui-no-synchronization/
Thanks! Now it works. Keep up the great work!