it’s nice that you want to make your own CalDAV server. That is quite a complex task… Local calendars can’t be synchronized automatically. If you need the local events you need to export them first, then import them again into an existing DAVdroid account.
A KeyStore exception is popping up when you have problems with the encryption. Keep in mind that if using encryption your server and your client (Android) must have at least one cipher that can be used for the encryption.
What do you mean with the REPORT query? DAVdroid is using it.