NextCloud Notification Emails

Nextcloud version 10.0.2
Operating system and version NethServer 7.3

I have NethServer connected AD to a Zentyal Domain, and all users show up in NextCloud and work great.
But, for each user, in the Personal settings, the email is blank and not editable, so I can get no notifications etc.
Is this a known issue, or is there something I can change to make this field editable.
The email field is filled out on Zentyal, and the emails exist for the user on NethServer, but nothing shows on NC.

Solved thanks to dnutan on NS forums, posted here in case it helps anyone else.
I don’t use AD in NethServer, but connect to a Zentyal AD through NethServer, and using userPrincipalName in the Email field in NC LDAP settings as below worked.