Or just that is can’t work, the first step is to run the Linux command:
service httpd configtest
This should show any errors.
If you still get a error then you need to monitor the error_log file while you try to restart apache:
tail -f /usr/local/apache/logs/error_log
If you have a server with DWHS Website Hosting and you are hell bent on fixing it yourself instead of putting in a ticket, next you might want to run easyapache from your WHM, 90% of the time this will fix any errors.