Hi,
One of my client's site has this plugin installed and it works fine, with one small issue, some emails fail to validate, specifically emails with a dot or an underscore fail to validate. For example john.doe@somewhere.com will not validate, as well as jay_jr@someplace.com any ideas, I wen't through the code, but the php class uses wordpress's built in is_email() function. The ajax query string will look like this for the XHR
http://www.bluedogbeverages.com/index.php?ns_mc_number=2&ns_widget_mailchimp_email=jay.jr%40powellssweetshoppe.com
I changed the name in the email for privacy purposes, any help is much appreciated.