There currently is not a way to automatically add all Domains to a new Admin User if the Admin is a Local Account. You would have to add all Domains individually to the local user account. There has been a feature request submitted to add this functionality in the future.
As a workaround, you can however implement this if you were to create an Admin Auth server and authenticate the Users via Radius. You would simply need to create a platform Administrator (firstname.lastname@example.org) and then add the Platform Role as well as all the Domains to this Platform Admin. Next, you would want to create an Admin Auth Server to authenticate the user via a Radius Server. In the Admin Auth server, you would want to create an authenticate rule to match the attribute returned to by Radius for the user and assign that user to the email@example.com Role.
For more on creating an Admin Auth Server, please refer to page 41 in the Admin Guide for vWLAN 2.2.1 and Later https://supportforums.adtran.com/docs/DOC-5271
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