Invalid command ‘Header’, perhaps misspelled or defined by a module not included in the server configuration
root@linux:# service apache2 restart * Restarting web server apache2 [fail] * The apache2 configtest failed. Output of config test was: AH00526: Syntax error on line XX of /etc/apache2/sites-enabled/site.conf: Invalid command 'Header', perhaps misspelled or defined by a module not included in the server configuration Action 'configtest' failed. The Apache error log may have more information.
Решение: необходимо подключить модуль headers
root@linux:# a2enmod headers Enabling module headers. To activate the new configuration, you need to run: service apache2 restart
И не забываем перегрузить apache
root@linux:# service apache2 restart * Restarting web server apache2 [ok]