First, thank you for making this easy and useful plugin availabel for free.
I just wondered about the following:
My father wanted to subscribe on my blog wwww.fishmoneyblog.com but never gets a confirmation email.
His email address I must say is a lttle odd though i.e. Name.firstname.lastname@example.org
First I contacted his provider cause I thought my domain for some reason was blacklisted. The answer was negative.
I then contacted my own hosting company and after investigating the matter, they said the particular message never arrived their mailserver hence suggesting maybe something wrong with my site.
I don’t know anybody else who has this ‘two dotted’ email address but for testing purposes I could create a new gmail account. In the meantime I kindly ask you if you know about this problem.