[Mailman-Users] Mail being relayed from one email, but not others

I have Mailman 2.1.5 running on Postfix. My postfix server and Mailman are running on server5.server.com (for simplicities sake). If I send an email from [EMAIL PROTECTED] it gets forwarded to all members of the mailing list. But if I send an email from any other member of the list nothing

[Mailman-Users] No mail going out

I just set up Mailman and set up a test list. Whomever I subscribe to the list receives a welcome e-mail. But then no one receives anything sent to the list there after. I've checked all the logs and there are no errors showing up. My syslog even shows it receiving the message and sending i