Invalid command 'Header', perhaps misspelled or defined by a module not included in the server configuration

Problem:

# tail -f ../logs/error.log

[Tue Jul 09 13:32:24 201x] [alert] [client 10.26.45.83] /folder1/folder2/.htaccess: Invalid command 'Header', perhaps misspelled or defined by a module not included in the server configuration
[Tue Jul 09 13:32:25 201x] [alert] [client 10.26.45.83] /folder1/folder2/.htaccess: Invalid command 'Header', perhaps misspelled or defined by a module not included in the server configuration

Solution:

Step 1: Enable header module

                # vi httpd.conf

LoadModule headers_module modules/mod_headers.so

Step 2: Restart the http server

                # service httpd configtest

                # service httpd restart