[SOLVED] Email field missing at registration

I'm trying to activate a payment plan that guests can subscribe at registration.
I don't know what I did in order get the result in the enclosed screenshot. As a matter of fact registrants are stuck in their process as email is mandatory but I no longer manage to have the field filled at registration.
I went around trying to fix it but I'm getting lost with the interactions among the different CB features.
The only third party component I'm using is AddUserFrontend (for staff use) but I've never had problems with it.
How can I have a regular email field showing again?

Edit the email field within CB > Field Management and under Parameters > Layout ensure you didn't override the Registration Value Layout or ensure your override includes [value].

Thanks a lot!
Everything's fine now.