TalentCards allows you to promote any user that you want to admin in order to have some extra help for managing the portal.
You can read more on this article.
If you are not able to fulfill your request and see an error message (1) it means that the user has already created her/his own TalentCards account using the same email address.
An account owner, in fact, cannot be an administrator to another portal, as the email address accross all TalentCards portal must be unique.
If you fall into this error, we suggest you follow one of these solutions:
Update the email address of your user in your portal (use a different email address)
Ask the users to change the email addresses in their own portals
Ask the owner of the other portal to contact the TalentCards support team and ask to delete the related account