SSL breaks CTA

When I try to enable SSL for a page that I have a call to action on, I get the following error as the CTA plugin is trying to load non-secure content. Any ideas on how to resolve?

[blocked] The page at ‘https://xxxxxxx.com/new/’ was loaded over HTTPS, but ran insecure content from ‘http://xxxxxxx.com/new/wp-content/plugins/cta/modules/module.ajax-get-variation.php?cta_id=29&_=1403928299092’: this content should also be loaded over HTTPS.

Thanks for any help

https://ww.wp.xz.cn/plugins/cta/