In a support discussion titled “How to block email for registration?”, SidV asked how to block registrations from specific email domains (e.g., *@email-service3.com). cpradio replied that this can be done by adding the domain to the “email domains blocklist” in Admin > Settings. SidV thanked cpradio enthusiastically. Later, BradCray clarified that the setting has since been renamed to “blocked email domains” and is now located under Admin > Settings > Login, for the benefit of future readers. codinghorror acknowledged BradCray’s note and edited earlier posts to reflect the updated terminology, suggesting a broader search-and-replace for “blacklist” and “whitelist” terms across Meta topics to ensure consistency, especially those with high view counts.
Hello team., I’ve been searching the possibility to block an email’s domain.
For example:
A few people register with *@email-service3.com.
There are good people, I could ask them to change the email service, that’s ok… but, how could I block that email’s service for new registrations?
Is it possible?
Yup, add it to email domains blocklist in Admin > Settings
Yes!!! I always said it. You rock! 
Thanks CpRadio !
Para os demais que estão chegando a este tópico como referência, assim como eu: acredito que essa configuração tenha sido renomeada para domínios de e-mail bloqueados e que possa ser encontrada em Admin > Configurações > Login.
-Brad