# iOS Carddav account verification failed **URL:** \ **Category:** 📱 Desktop & mobile clients\ **Created:** [November 30, 2020, 8:40pm UTC](https://help.nextcloud.com/t/ios-carddav-account-verification-failed/99798 "2020-11-30T20:40:53Z")\ **Posts on this page:** 1\ **Showing post:** 2
**Author:** ![j-ed](https://help.nextcloud.com/user_avatar/help.nextcloud.com/j-ed/32/7281_2.png) [@j-ed](https://help.nextcloud.com/u/j-ed)\ **Post date:** [December 1, 2020, 9:51am UTC](https://help.nextcloud.com/t/ios-carddav-account-verification-failed/99798/2 "2020-12-01T09:51:23Z")
Using the search function of this forum I found the following information: > [@\[Help\] NC11 + Mac Sierra Contact Sync URL](https://help.nextcloud.com/t/help-nc11-mac-sierra-contact-sync-url/7560/2): > > No bug in NC. Apple (both macOS and iOS) need the principal URL. Other clients need the address book url. also see [https://docs.nextcloud.com/server/11/user\_manual/pim/sync\_osx.html](https://docs.nextcloud.com/server/11/user_manual/pim/sync_osx.html) wink Would it be possible to simplify enrollment by performing server-side checks to determine client platform and redirect accordingly? No, because macOS Contacts will also access [https://FQDN/remote.php/dav/addressbooks/users/USER@TLD.COM/contacts/](https://FQDN/remote.php/dav/addressbooks/users/USER@TLD.COM/contacts/). And generally returning different results for different u… Additionally the Nextcloud user guide provides detailed information how to sync data: [https://docs.nextcloud.com/server/20/user\_manual/en/pim/sync\_ios.html?highlight=contact#contacts](https://docs.nextcloud.com/server/20/user_manual/en/pim/sync_ios.html?highlight=contact#contacts) --- _[View the full topic](https://help.nextcloud.com/t/ios-carddav-account-verification-failed/99798)._