When accessing the website OR any URL, error log file /usr/local/apache/logs/error_log shows error as below.
SecurityException in Application.cpp:188: Do not have root privileges. Executable not setuid root?
This is because the suphp binary is missing its sticky/suid permissions. Login to your server and correct the permissions with command below.
# chmod +s /opt/suphp/sbin/suphp