Filter "prioritize_critical_css" is not working

[B Anjaneyulu Reddy]

Hello Brothers & Sisters,

I've enabled prioritize_critical_css filters on my Apache server hosted on AWS EC2 instance. Here is my current pagespeed.conf file located in /etc/httpd/conf.d/. Our application was developed using Laravel & CSS/JS files are combined, minified & versioned using Elixir (built on gulp)

ModPagespeedUseExperimentalJsMinifier on

ModPagespeedEnableFilters prioritize_critical_css 

ModPagespeedEnableFilters defer_javascript

ModPagespeedEnableFilters combine_css 

ModPagespeedEnableFilters combine_javascript 

ModPagespeedEnableFilters rewrite_javascript 

ModPagespeedEnableFilters collapse_whitespace 

ModPagespeedEnableFilters rewrite_images

ModPagespeedEnableFilters recompress_images 

ModPagespeedEnableFilters move_css_to_head 

ModPagespeedEnableFilters move_css_above_scripts 

ModPagespeedEnableFilters rewrite_css,sprite_images 

ModPagespeedEnableFilters lazyload_images

ModPagespeedEnableFilters resize_rendered_image_dimensions

ModPagespeedEnableFilters extend_cache

However, I feel that the filters does seems to work. In pagespeed insights, I still get the following error for CSS (the single file):

Eliminate render-blocking JavaScript and CSS in above-the-fold content

Your page has 1 blocking CSS resources. This causes a delay in rendering your page.

None of the above-the-fold content on your page could be rendered without waiting for the following resources to load. Try to defer or asynchronously load blocking resources, or inline the critical portions of those resources directly in the HTML.

Question:

• How do I fix this issue? I believe if that if the above filter worked fine, this issue would have been solved.
• Any suggestions to add (or remove) recommended filters for best performance of our web application?

Thanks in advance,

Anji