Prevent multiple quiz submissions

Hello.

We would like to prevent users from submitting the quiz multiple times, based on email and/or phone number.

I see these two related topics:

1. https://wordpress.org/support/topic/prevent-resubmission/
2. https://wordpress.org/support/topic/restrict-form-submissions-on-duplication-of-email-and-user-name/

But neither seems to work, and perhaps are both about “normal” forms (i.e. Contact, etc.), and not so much about “Leads” forms.

I have gone into the Leads form and activated “Enable inline validation (as user types)”, but I can still register and submit as many times as I like using all of the exact same info…

Any recommendations? Am I doing something wrong?

Thanks!

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