I've been grappling with this issue for a few days. I know per the wiki that I need to compile custom php5 with imap activated to work with the Mailhandler module in Drupal. I finally (I believe) have this compiled correctly. If I check via phpinfo IMAP shows up as one of the extensions. Now, when I go to mailhandler and attempt to test the connection I get the same issue of 'Couldn't open stream.'
I'm wondering if I am just messing up the email settings in mailhandler. I want mailhandler to pop in and check my Mailman list, from there I will set up Listhandler and be on my way.
The mailman addresses are at lists.mydomain.com not mydomain.com - this presents some confusion. I've tried many different combinations of mail server addresses and email addresses and none seem to work.
I would love to get some advice from anyone who has experience with this setup. In fact, I'd be happy to pay someone to consult with us on this issue.
Thanks for any suggestions or information,