Caldav connection with ios


I want to connect my iphone calendar with nextcloud via caldav. If I connect the phone internal via IP address id works fine, but if I would connect via internet http://myserver/nextcloud/remote.php/dav/principals/users/xxx/ it doesn’t work.

I don’t know why, should I open any Ports?

Thank you

We don’t know your network setup. But your Nextcloud setup needs to be accessible from outside your home in order to sync the calendars as well. If you haven’t opened any ports yet, you’ll probably have to do it. But there are no ports specifically for caldav or carddav only, they all pass through http/https (80/443).