If you are getting the following error in your apache logs then you should probably load “mod_headers.so” to your apache server.
Invalid command 'Header', perhaps misspelled or defined by a module not included in the server configuration
If you are using Centos server then you need to edit your apache configuration file and add the following line
LoadModule headers_module modules/mod_headers.so
If you are using Ubuntu based Operating system then you need to do the following and restart your apache service.
cp -arp /etc/apache2/mods-available/headers.load /etc/apache2/mods-enabled/headers.load
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