function is_valid_email_domain($login, $email, $errors ){
$valid_email_domains = array("gmail.com","yahoo.com");// whitelist email domain lists
$valid = false;
foreach( $valid_email_domains as $d ){
$d_length = strlen( $d );
$current_email_domain = strtolower( substr( $email, -($d_length), $d_length));
if( $current_email_domain == strtolower($d) ){
$valid = true;
break;
}
}
// if invalid, return error message
if( $valid === false ){
$errors->add('domain_whitelist_error',__( 'Hata !: Sadece gov.tr uzantılı e-posta adresleri ile kayıt olabilirsiniz.' ));
}
}
add_action('register_post', 'is_valid_email_domain',10,3 );
Olmazsa aşağıdaki eklentiyi dene:
https://wordpress.org/plugins/restrict-new-users-by-domain/