I use CM to collecting e-mail sign-ups for a monthly webinar I do. The problem I have is a number of people who sign up never receive the simple plain text verification e-mail. Thanks to CM team, I now can check how many subscribers never clicked through on the confirmation e-mail. However, I am at a loss to explain why these confirmation e-mails never made it through. Most of them seem to be e-mails from legitimate subscribers who use their work e-mail address. Any suggestions?