In the registration form the “E-mail (Not Unique)” option does not work for me

Good morning to all of you.

I ask for your support to see if it is possible to solve the following problem:

Context: My need is that in the ultimate members Registration form, I can manage the same email for different accounts. (Different Users)

For example, if someone decides to acquire 5 accounts for my service (Each account manages a unique user), in the registration data I require that the person who is going to acquire said accounts can register each of them with the same email.

Currently it seems the default configuration is that the main email of the account cannot be repeated, if I try to register a second account using the same email I am shown a notice “The email you entered is already registered”.

When I configured the main email field I put the “E-mail(Not Unique)” option in the validation field but it doesn’t work. What I need to do?

The page I need help with: [log in to see the link]