I've gotten Mutt to work on several machines and have come to quite like it. I use fetchmail to get the mail, procmail and formail to process it, and msmtp to send it. I do not run my own mail server; I use Mutt to send and receive mail from my internet email providers.
The primary resource I used to get it working was this:
http://docs.huihoo.com/gentoo/resour...e-to-mutt.html
Do you receive any error messages when you send mail?
What mail sending agent are you using it and what are the contents of the associated rc file, at least the part relevant to sending mail? (Take care not to post any information you wish to remain confidential, such as usernames and passwords.)