disappearing mailman archive

recently a user emailed me asking about a broken link, it was to a VM mailman list archive. The automatically generated link to the listinfo page at the bottom of each mailman mail received works, but the listinfo page's link to the archive leads only to an attachment folder, no mail bodies. I don't know where the archive is supposed to be so I can check. Anyone?

Dave

ps but I don't know when this started happening but can confirm that it used to work