Recently, our administration enforced authentication and I had to go into the settings of lm_prefs.php, set $smtp_auth=true and add the necessary details in the following two parameters ($smtp_host, $smtp_port). Now the problem is that the unsubscribe process is not working properly. Specifically, when the user clicks on the unsubscribe link, (i) an empty page in browser opens with no content, (ii) the user doesn't receive an email that he has unsubscribed and the link to re-subscribe, (iii) the admin doesn't receive a notification that the user has unsubscribed. The unsubscribe link per se works and the user is removed from the list. Can you please help here? Thanks.