My Exchange2013 service requires 3 things for login - servername, "Sam Account Name" ( not username!) and password. Also TLS is required.
So, my bounce settings look like this:
$bounce_protocol ='pop'
$bounce_mailbox_host = 'webmail08.mycloudwebguys.com';
$bounce_mailbox_user = 'bounce_samname'; // note: SAM account name, not UserName!
$bounce_mailbox_port = "993/ssl/novalidate-cert";
It WOIKS!!!!
You wouldn't believe how many permutations I went through before I hit on it.
Hope this helps somebody
