Hmm, could thus have caused some issue with the port httpd is listening on? With Nginx listening on 80/443 the httpd is set to listen on 8181, both specified in /usr/local/apache/conf.d/vhosts.conf and /usr/local/apache/conf/httpd.conf.
Yet it would not start with this error
(98)Address already in use: AH00072: make_sock: could not bind to address 0.0.0.0:80