Auto login doesn't work after active Pro Sites plugin

Hi

I found a code to auto login after activate users with activation link on WPMU and it works fine. But after install Pro Sites and active the plugin, users account are activate by click on activation link, but not login to the site and i get a with page with header.

For auto login I used this code in my functions.php:

function auto_login_new_user( $user_id, $email, $meta ) {
$user = new WP_User( (int) $user_id );
$creds = array();
$creds['user_login'] = $user->user_login;
$creds['user_password'] = $meta['user_pass'];
$creds['remember'] = true;
$user = wp_signon( $creds, false );
wp_set_current_user($user->ID);
if ( is_wp_error($user) ) {
echo $user->get_error_message();
} else {
// safe redirect to actually login the user - otherwise they would need to manually refresh the page
// PLUS: this clears the activation confirmation page with the plain text password printed on screen
wp_safe_redirect( get_home_url() );
exit;
}
}
add_action( 'wpmu_activate_user', 'auto_login_new_user', 10, 3 );