I just tried this way in login-form.php, but it doesn′t work neither.
<?php
function auto_login_new_user( $user_id ) {
wp_set_current_user($user_id);
wp_set_auth_cookie($user_id);
wp_redirect( ‘https://www.example.com/’ );
exit;
}
add_action( ‘new_user_activated’, ‘auto_login_new_user’ );?>