Invalid command ‘SSLEngine’, perhaps misspelled or defined by a module not included in the server configuration – enable apache ssl module

If you are moving an existing Apache configuration file from one server to another,  or if you are enabling SSL configuration on an existing website,  you could run into this error as you restart apache

server#/etc/init.d/apache2 restart
Invalid command 'SSLEngine', perhaps misspelled or defined by a module not included in the server configuration

This essentially means that Apache doesn’t understand what the SSLEngine command means.   This is most likely because SSL has not been enabled on this server.  For quite some time SSL has come with Apache2 by default,  however you do still have to enable it.

To enable it you can simply run enable the ‘ssl’ apache module the command

#a2enmod ssl
#/etc/init.d/apache2 reload #or
#/etc/init.d/apache2 restart

The error should no longer show a the SSLEngine command is correctly recognized by the ssl mod.