Cannot add Expires headers in WordPress

Question

Been trying to get rid of the "Add Expires headers" in GTmatrix, with no success. I've installed the WP Fastest Cache plugin and tried a bunch of different variations to .htaccess that I found on stackoverflow and some other websites where people had similar questions, with no success - GTmatrix still shows the same error.

This is my current .htaccess:

# BEGIN WpFastestCache
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteCond %{HTTPS} =on
RewriteCond %{HTTP_HOST} ^domain.com
# Start WPFC Exclude
# End WPFC Exclude
# Start_WPFC_Exclude_Admin_Cookie
RewriteCond %{HTTP:Cookie} !wordpress_logged_in_[^\=]+\=username
# End_WPFC_Exclude_Admin_Cookie
RewriteCond %{HTTP_HOST} ^domain.com
RewriteCond %{HTTP_USER_AGENT} !(facebookexternalhit|Twitterbot|LinkedInBot|WhatsApp|Mediatoolkitbot)
RewriteCond %{HTTP_USER_AGENT} !(WP\sFastest\sCache\sPreload(\siPhone\sMobile)?\s*Bot)
RewriteCond %{REQUEST_METHOD} !POST
RewriteCond %{REQUEST_URI} !(\/){2}$
RewriteCond %{REQUEST_URI} \/$
RewriteCond %{QUERY_STRING} !.+
RewriteCond %{HTTP:Cookie} !comment_author_
RewriteCond %{HTTP:Cookie} !woocommerce_items_in_cart
RewriteCond %{HTTP:Cookie} !safirmobilswitcher=mobil
RewriteCond %{HTTP:Profile} !^[a-z0-9\"]+ [NC]
RewriteCond %{DOCUMENT_ROOT}/wp-content/cache/all/$1/index.html -f [or]
RewriteCond /home/user/public_html/wp-content/cache/all/$1/index.html -f
RewriteRule ^(.*) "/wp-content/cache/all/$1/index.html" [L]
</IfModule>
<FilesMatch "index\.(html|htm)$">
AddDefaultCharset UTF-8
<ifModule mod_headers.c>
FileETag None
Header unset ETag
Header set Cache-Control "max-age=0, no-cache, no-store, must-revalidate"
Header set Pragma "no-cache"
Header set Expires "Mon, 29 Oct 1923 20:30:00 GMT"
</ifModule>
</FilesMatch>
# END WpFastestCache
#Customize expires cache start - adjust the period according to your needs
<IfModule mod_expires.c>
  FileETag MTime Size
  AddOutputFilterByType DEFLATE text/plain text/html text/xml text/css application/xml application/xhtml+xml application/rss+xml application/javascript application/x-javascript
  ExpiresActive On
  ExpiresByType text/html "access 600 seconds"
  ExpiresByType application/xhtml+xml "access 600 seconds"
  ExpiresByType text/css "access 1 month"
  ExpiresByType text/javascript "access 1 month"
  ExpiresByType text/x-javascript "access 1 month"
  ExpiresByType application/javascript "access 1 month"
  ExpiresByType application/x-javascript "access 1 month"
  ExpiresByType application/x-shockwave-flash "access 1 month"
  ExpiresByType application/pdf "access 1 month"
  ExpiresByType image/x-icon "access 1 year"
  ExpiresByType image/jpg "access 1 year"  
  ExpiresByType image/jpeg "access 1 year"
  ExpiresByType image/png "access 1 year"
  ExpiresByType image/gif "access 1 year"
  ExpiresDefault "access 1 month"
</IfModule>
#Expires cache end
# BEGIN Cache-Control Headers
<IfModule mod_expires.c>
  <IfModule mod_headers.c>
    <filesMatch "\.(ico|jpe?g|png|gif|swf)$">
      Header append Cache-Control "public"  
    </filesMatch>
    <filesMatch "\.(css)$">
      Header append Cache-Control "public"
    </filesMatch>
    <filesMatch "\.(js)$">
      Header append Cache-Control "private"
    </filesMatch>
    <filesMatch "\.(x?html?|php)$">
      Header append Cache-Control "private, must-revalidate"
    </filesMatch>
  </IfModule>
</IfModule>
# LBROWSERCSTART Browser Caching
<IfModule mod_expires.c>
ExpiresActive On
ExpiresByType image/gif "access 1 year"
ExpiresByType image/jpg "access 1 year"
ExpiresByType image/jpeg "access 1 year"
ExpiresByType image/png "access 1 year"
ExpiresByType image/x-icon "access 1 year"
ExpiresByType text/css "access 1 month"
ExpiresByType text/javascript "access 1 month"
ExpiresByType text/html "access 1 month"
ExpiresByType application/javascript "access 1 month"
ExpiresByType application/x-javascript "access 1 month"
ExpiresByType application/xhtml-xml "access 1 month"
ExpiresByType application/pdf "access 1 month"
ExpiresByType application/x-shockwave-flash "access 1 month"
ExpiresDefault "access 1 month"
</IfModule>
# END Caching LBROWSERCEND


# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>

# END WordPress

Answer 1

Please check mod_expires module is enabled on your server’s main configuration file

You can check this with your hosting provider or if you have access to the httpd.conf file the following line should be un-commented so expires headers works:

LoadModule expires_module modules/mod_expires.so

Or It may chances that problem associated with your plugin. You can check with trying this lightweight plugin for adding expires headers. It may not serve your whole purpose but help to find out that your plugin working fine or not.

Answer 2

I solved the problem with the following steps: First checked my apache site configuration and make sure AllowOverride all present like below.

<Directory /var/www/mysite>
    AllowOverride all
</Directory>

Then tried the following commands:

sudo a2enmod rewrite
sudo a2enmod headers 
sudo a2enmod expires
sudo service apache2 restart