I was having the worst time setting up my mail.com account server settings, and I imagine others have as well - especially when it came to getting you mail to send. There's very little advice on the topic, none I've found specific to the Droid line up and, the mail.com recommended settings are false bits of trash. For one, you don't need to set up IMAP settings, POP service is free. First, ignore them and enter these settings.
Port is 995
Your mail.com email address, whatever your suffix is (mine ends in chemist.com)
Check secure connection, do not check verify certificate
Port is 587
Email address and password as above
DO NOT CHECK SECURE CONNECTION OR VERIFY CERTIFICATE- this will cause all of your sent messages to fail.
I hope this helps. It took me 2 days of frustration to figure out the problem.
Sent from my DROID2 using DroidForums