Access for specific users by defining whitelist

By the way any kind of WordPress hook “in the middle” of the registration’s validation process that lets me check the user’s e-mail address on my own would also help me.

Ok, I just found the um_submit_form_errors_hook_ hook which uses the um_submit_form_errors_hook_() function as callback in ultimate-member/core/um-actions-form.php (at line ~150).

With this hook I can add my own (whitelist) validtions for e-mail values on registration. Seems to be the right place for me.?…At least my changes work properly there.

So, this is the Solution: I just used that hook (mentioned above) in my functions.php to add my e-mail check on top of the original checks that are made by UM.

Works like a charm.

Here is a little code snippet for adding that hook to your functions.php:

function my_awesome_submit_form_errors( $args ) {
// start your indiviual form validation here
// in case of doubt just copy some lines of code from the original um_submit_form_errors_hook_() function to get a feeling how it works
}
add_action( 'um_submit_form_errors_hook_', 'my_awesome_submit_form_errors', 10 );

That’s the right hook, before user registration (hook in form errors check)

Thanks for posting this useful tip