HTTP Headers Issues

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Operating system: CentOS 8, Apache - PHP-FPM

HTTP Headers

I am trying to add security headers and nothing is working. I have added to the webin httpd config, .htaccess, wordpress plugin and no change via any of those options

#Header set Cache-Control "no-cache, no-store, must-revalidate, max-age=0"
#Header always set Strict-Transport-Security “max-age=31536000;includeSubDomains”
#Header always append X-Frame-Options SAMEORIGIN
#Header set X-XSS-Protection "1; mode=block"
#Header set X-Content-Type-Options nosniff
#Header set Content-Security-Policy default-src 'self'; script-src 'self'; connect-src 'self'; img-src 'self'; style-src 'self';
#Header always set Referrer-Policy "strict-origin"

(yes i know those are commented out)

Also adding the following line gives an error 500 when trying to access wp-admin page:

#Header set Content-Security-Policy default-src 'self'; script-src 'self'; connect-src 'self'; img-src 'self'; style-src 'self';
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