Gzip compression isn't working

[Webspher]

Hello everyone,

I'm using pagespeed 1.11.33.4-0 for nginx, but i don't know why none of the static files are being compressed! here is the config I'm using, am I missing something?

Thanks for your help

pagespeed on;

pagespeed EnableFilters combine_css;

pagespeed EnableFilters combine_javascript;

pagespeed EnableFilters rewrite_css;

pagespeed EnableFilters rewrite_javascript;

pagespeed EnableFilters rewrite_style_attributes_with_url;

pagespeed EnableFilters remove_comments,collapse_whitespace,remove_quotes;

pagespeed DisableFilters rewrite_images;