if you are using centOs then use
sudo chown -R centos:centos /var/www/html
sudo chmod -R 755 /var/www/html
For Ubuntu
sudo chown -R ubuntu:ubuntu /var/www/html
sudo chmod -R 755 /var/www/html
For Amazon ami
sudo chown -R ec2-user:ec2-user /var/www/html
sudo chmod -R 755 /var/www/html