failed (13: Permission denied) while connecting to upstream
Sometimes you may face the above error on using Nginx as reverse proxy even if the configurations and permissions are correct.
This is because of the selinux policy and we can resolve this by disabling it.
As the temporary solution run the following command on terminal.
This will disable the selinux till the next reboot of the server.
In-order to disable selinux permanently, update the following line in the config file '/etc/sysconfig/selinux'.