Gzip not getting Enabled says HTML file ype is Inactive.

Gzip compression not getting Enable because of HTML file type is Inactive.and after checking and contacting my server I understood that it is enabled there but still in every Gzip compression test tool Gzip is still not enabled. I have tried NUmerous codes in my .htaccess but no Results. please help after checking default.config I have noticed that there is a connection between HTML and Default.modl.comfig.Last three days I am trying to Enable Gzip please help.