Emoticons not showing in lightbox

Hi there

When clicking the icon to insert an emoticon I just get a blank lightbox.

I run my admin over ssl but other than that I can’t think why this is.
Tested it on another of my sites not using ssl in admin and it works ok.

Just thought I should report it as a bug just in case.

https://www.ads-software.com/plugins/wp-emoji-one/