MailChimp Integration Error When Entering API Key

When enabling MailChimp Integration for the first time, after entering the API key, there’s an error.

The resulting url is:

And the error output is:

Notice: Undefined index: mailchimp_webhooks in plugins/mailchimp-sync/admin_page.php on line 279

Warning: Cannot modify header information – headers already sent by (output started at plugins/mailchimp-sync/admin_page.php:279) in wp-includes/pluggable.php on line 1171

Lots of gotchas in your software.

Interestingly enough, upon returning to the main plugin page, everything seems fine… until the next error!

  • Nastia
    • Support Rock Star

    Hello Phillip

    I hope you are doing well!

    I can reproduce the same on my installation and I have reported this to our developers. As soon as there is an update I will post bach in this thread.

    Please note, if you set the WordPress debug to false, these warnings will not be visible, and they do not affect the plugin’s functions.

    Thank you for reporting this to us!

    Kind Regards,


  • Phillip
    • Design Lord, Child of Thor

    I got around it with this:

    admin_page.php line 279

    #$webhooks = $_POST['mailchimp_webhooks'];
    if ( isset( $_POST['mailchimp_webhooks'] ) )
    $webhooks = $_POST['mailchimp_webhooks'];
    $webhooks = array('delete_user' => '', 'webhook_key' => '');

    Which is NOT a fix, it’s just a work around. But those keys need to be tested for at some point.

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