You can have a DNS resolving problem, or a apache configuration problem.
But as you are using clodflare, may be you have a apache configuration problem.
Start testing if your domain is resolving correctly to your server.
Run inside your server:
# host domain.com
If pointed to your server, check apache logs.
If no, fix you DNS problem.
When you assure your domain is resolving to your server, you can check if apache is serving your pages.
You must check your logs:
/usr/local/apache/logs/error_log
/usr/local/apache/logs/access_log
/usr/local/apache/domlogs/domain.com.error.log
/usr/local/apache/domlogs/domain.com.log
If they are served, you can fix the problems as pointed in your logs.
Regards,
Netino