Solution:
CardDAV does not support two factor authentication. Generate an app password for the account setup.
https://support.google.com/accounts/answer/185833?hl=en
Problem:
Adding a CardDAV account on the iPhone keeps giving account verification failed.
Better Solution:
cardDAV not needed. Go to iPhone Settings-> Contacts -> Default Account and set it to Gmail instead of iCloud
Problem:
iphone contacts won’t sync to gmail
Better Solution:
cardDAV not needed. Go to iPhone Settings-> Contacts -> Default Account and set it to Gmail instead of iCloud
Problem:
iphone contacts won’t sync to gmail
CardDAV account verification failed
