Let’s try to add hook this in your theme functions.php file:
add_action('template_redirect', function (){
if(class_exists('UltraCommunity') && !is_user_logged_in())
{
if(\UltraCommunity\Controllers\FrontPageController::getActivePageTypeId() === \UltraCommunity\Controllers\FrontPageController::PAGE_MEMBERS_DIRECTORY){
\UltraCommunity\Controllers\FrontPageController::redirectToLogInPage();
}
}
});
Let me know if it works for you!
~Mihai