Here is the Infusionsoft URL – https://on427-c6b35b.pages.infusionsoft.net/ – But if anyone provides their email address in that page’s form, they never receive the campaign email.
We would need a bit more information. What goal begins the campaign that sends the email. Are you using tags to start the contact in the campaign or some other goal? Also, a snapshot of the campaign and/or sequence in question would be helpful too.