I was recently working on a server with CentOS 6 installed and trying to configure Apache virtual hosts to host several domains / websites without any control panel like cPanel.
But after editing /etc/httpd/conf/httpd.conf file for virtual hosts, Apache was failing to start with below error message.
Login to your server as root via SSH.
Open /etc/httpd/conf/httpd.conf file in any text editor like nano.
Go to the line which is producing error message. It Should be something like below.
Change above line to below line.
CustomLog /var/www/domain.com/requests.log common
Save the file using: ctrl + O
Exit nano text editor: ctrl + X
Start Apache / http using below command.
service httpd start
Done!! Apache should start and run now.