Membership 2 MailChimp addon error

Activating the MailChimp addon in membership 2 Pro displays the following error on the MailChimp settings screen:
Fatal error: Cannot use object of type WP_Error as array in /home3/jefe442/public_html/mysite.com/wp-content/plugins/membership/lib/mailchimp-api/Mailchimp.php on line 61