Running yast http-server module, making basically no changes to get basic
config. No vhosts, ssl, etc.

Btw a server name can't be entered, the value is going to /dev/null.

Starting apache gives:
Mar 27 14:37:35 cubie start_apache2[9361]: Module "authz_default" is not
installed, ignoring.
Mar 27 14:37:35 cubie start_apache2[9361]: Check the APACHE_MODULES setting in
/etc/sysconfig/apache2.
Mar 27 14:37:35 cubie start_apache2[9361]: AH00526: Syntax error on line 10 of
/etc/apache2/mod_status.conf:
Mar 27 14:37:35 cubie start_apache2[9361]: Invalid command 'Require', perhaps
misspelled or defined by a module not included in the server configuration
Mar 27 14:37:36 cubie start_apache2[9378]: Module "authz_default" is not
installed, ignoring.
Mar 27 14:37:36 cubie start_apache2[9378]: Check the APACHE_MODULES setting in
/etc/sysconfig/apache2.
Mar 27 14:37:36 cubie start_apache2[9378]: AH00526: Syntax error on line 10 of
/etc/apache2/mod_status.conf:
Mar 27 14:37:36 cubie start_apache2[9378]: Invalid command 'Require', perhaps
misspelled or defined by a module not included in the server configuration
Mar 27 14:37:36 cubie systemd[1]: Failed to start The Apache Webserver.

In the yast http-server server-modules tab authz_default is listed with a
description of "unknown", i.e. none. The module does not exist on disk!

Editing /etc/sysconfig/apache2 adding authz_core to APACHE_MODULES makes
authz_core also be shown with a description of "unknown".

systemctl restart apache2
is now successful.

This bnc:835484#6 basically says yast http-server module is foobared, so it's
probably best to uninstall it.