I've been trying to set up my "bounce" responses through this plugin and it doesn't seem to be working with my Google Apps email account (which has correct credentials and pop enabled). I've been communicating with my hosting provider, ICDSoft and here's their response to my problem.
We checked this. It seems that the plugin has problems connecting to servers on port 995. We are not restricting the access, so it has to be a problem with the plugin itself. If you connect on port 110 (the default non-SSL port}, the script seems to work. However, Gmail do not support a port other than 995 as far as we know. Please note that you can't have one email address with us, and the others with Gmail.
Do you have any suggestions on a fix?