This thread is resolved. Here is a description of the problem and solution.
Problem: One certain CSS file is loading thru my website's http: version which is supposed to be in https: to make the whole website secured. How to fix that?
Solution: This can be solved with few steps, please redirect SSL files properly, we recommended using this plugin for SSL setup as other clients have confirmed that this works good with WPML: https://wordpress.org/plugins/really-simple-ssl/
After that, please clear all sort of caches in your site plugin cache (if any) / CDN cache (if any) / browser cache and then check, it will resolve the issue.
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