The functionality you are asking for has already existed in the plugin. when you enter the domains in the whitelist area then only those domains are allowed for the registration on the site, other domains will auto blocked for registration.
Hi @kalidarn
This plugin offers both functionalities for you. In the plugin setting, you can enter blacklist domains and whitelist domains, If you enter the domains in the blacklist area then all those emails or domains will be blocked for registration, same like if you enter the domains in the whitelist area then the user can register on your site only with those domains.
