[Mailman-Users] Sent Once, Received Three Times

I'm using MailMan as an advertising safelist for my website. I just sent out an ad through the safelist one time, but it appears that I sent it three times. This puts me at risk of being accused of spam, since I only allow one ad per day per member.

Does anyone know why this happened? What can I do to prevent this from reoccurring?

Scott Wilson BeachFrontAds.com

Classified Ads & Safelist http://www.beachfrontads.com/