mass email sender sends to empty recepients?

I sent out an email with a link to a poll to all members and checked the result in a plugin called email log that logs all emails going through a wordpress installation. the screen shot is attached. every 3rd or so recipient is empty? I am not sure what happened here...

JOIN 396028 HAPPY MEMBERS

We pride ourselves on our level of customer support and responsiveness to member requests. Your WordPress experience will never be the same


Start free trial