e-Newsletter 1.2.5 fails bounce test

Hi

I'm trying this out because I couldn't get v1.2.4 working.

1. When I try to send a bounce test, I get this error:

<br />
<b>Warning</b>:  imap_open() [<a href='function.imap-open'>function.imap-open</a>]: Couldn't open stream {mail.unlimited-space.com:995/pop3/notls/ssl}INBOX in <b>/home/screenwi/public_html/wp-content/plugins/e-newsletter/e-newsletter.php</b> on line <b>1543</b><br />
Can not authenticate to POP3 server: Authentication failed.

I'm logged in as administrator, WordPress 3.5.1. Any help would be great. My client can't send newsletters.

Thanks