Ajaxy Live Search only working on secure https:// pages

We’re having an issue where the plugin only returns live results on https:// pages. Non-secure (http://) pages give the following error:

XMLHttpRequest cannot load https://eatboutique.com/wp-admin/admin-ajax.php. The 'Access-Control-Allow-Origin' header contains multiple values 'http://eatboutique.com, *', but only one is allowed. Origin 'http://eatboutique.com' is therefore not allowed access.

So, instead of returning results on non-secure pages, it simply displays the progress animation indefinitely. Only a few of our pages are secure, so unfortunately this means the plugin is not working on the majority of the site pages/posts.

Does anyone have a solution for this problem? Thanks in advance.

https://ww.wp.xz.cn/plugins/ajaxy-search-form/