CalDAV synchronization with iOS 10.3.3

Hello, nextcloud server does not synchronize CalDAV with iOS 10.3.3 gives an error credential verification failed, and all the data is entered correctly, everything was done according to the instructions from the official site, but nothing works, what nuances can tell me please? Thank you.

First make sure, that service discovery is working:

If service discovery is working on your server, follow this steps (this works for me and friends of mine very reliable):

  1. delete eventuelly existing caldav accounts using your nextcloud-instance ( from your clients (Mac/iOS).

  2. to add a caldav-account on your iOS-device:
    go to “settings” --> “accounts+passwords” --> “add account” --> “other” --> “add caldav account”
    As server enter only the domain name nothing else (in your example this would be “”). Also enter username and password for the nextcloud user and hit “proceed” in the upper right corner.

  3. to add an caldav-account on your Mac:
    go to “system preferences” --> “internet accounts” --> “other” --> “add caldav account” (I am not in front of my Mac right now - might be slightly differently).
    Then choose „automatic“ configuration. As username enter (where USERNAME is your Nextcloud username) and the according password.