Hey there,
Awesome, glad to hear. As a heads up, MailChimp actually offers a specific Birthday field type, which you may consider using in place of the current “text” Birthday field that’s active on your signup form. Of course, it’s not required, so if you prefer the text option, feel free to continue using that, but just wanted to let you know that a Birthday field type is available!
In regards to the error message you’re seeing, that’s definitely a bit odd, and I can replicate that happening on my end when trying to use your signup form as well.
I’d recommend first double-checking your list inside of your MailChimp account to ensure that you have no required fields outside of what’s visible on your signup form (so, make sure that “Email Address”, “First Name”, and “Birthday” are the only required fields on your list). Once you’ve done that, log back into your WordPress admin area and go to th eplugin’s settings. From there, click the “update list” button at the top, which should refresh things. Finally, give the signup form another try to see if the issue’s been resolved.
If you’re still seeing the error message, I’d recommend disconnecting the MailChimp account from the plugin (by using the “log out” button in the settings) and reconnecting. You may also consider uninstalling and reinstalling the plugin if the above does not work as well.
If you’re still seeing issues, feel free to send me an email at mailchimptk[at]gmail.com with a link to your Mailchimp-hosted signup form (https://kb.mailchimp.com/article/how-do-i-share-my-signup-form) , and I can take a closer look from there.