Hello,
Can you please share where you are getting this error?
Also, are you using our plugin “MailChimp for WordPress”?
Yes we are using plugin MC4WP: Mailchimp for WordPress. This happen when the premium plugin is installed along with the free one and ajax form submission is selected. But the strange thing is, it only throws the error exception but still able to create the entry on mailchimp list. Below are the plugin we are using and corresponding version:
MailChimp for WordPress – Premium (Version 3.3.11)
MC4WP: Mailchimp for WordPress (Version 4.7.4)
Plugin Contributor
Lap
(@lapzor)
Since you are a Premium user please contact us on support @ mc4wp.com for Premium support. You can just email us a link to this thread and Premium support will pick it up from there.
Thanks