I'm trying to set this up. I have run through the documentation and have successful added a subscriber using the testing codes here:https://wiki.foxycart.com/integration/mailchimp_test
But it isn't working as I go through the checkout checking the newsletter checkbox.
I have this in my fc-mailchimp.php and the option selected in my Admin to allow users to sign up for your newsletter, and I have tripped checked all API keys are correct, but no joy.
$Custom_Field = 'newsletter_subscribe';
$Custom_Field_Value = '1';
My checkout is in Test mode does it not work until it's live?