Steven Jones writes:

I just upgrade Mailman but for some reason it seems to be talking to postfix on ::1 and postfix does a relay deny....For mailman is this normal? Or do I have a misconfiguration?

I gather that you had a working Mailman installation that stopped working on upgrade. If it formerly worked with Mailman talking on IPv4 loopback, and now it doesn't because it's on IPv6, then Postfix is probably misconfigured. You need to tell it that IPv6 loopback is just as much "localhost" as IPv4 loopback is.

Otherwise, you need to provide more information.