Thank you rfc2822.
Now, I configured the webserver that runs nextcloud to also send the certificate chain file of letsencrypet. Now, Davdroid is happy - so am I 🙂
Link local contacts to davdroid as mentioned in FAQ?
Using an S5 running LineageOS (android 7.0.1)
To move the contacts from your local addressbook to your DAVdroid account (and thus your CardDAV service), you may either:
export your Android contacts from your local account (Contacts / Export to .vcf file) and import them into your DAVdroid account (Contacts / Import from .vcf file)
I don’t see any option in the app to import from contacts to davdroid account. I’ve got local contacts on my phone or a vcf file I’d like to use. My cardDav server is on my nextcloud server. I can’t simply import the contacts to nextcloud because I get an error saying my vcard file is not version 4 or 3 (tips on how to convert my vcard file to one of those versions is welcome too).