Verify the OS you have in your server, based on that you proceed with the installation.

In case if it is CentOS7, then run the following command

## Run these commands as root user

1. mkdir /etc/yum.repos.d/backup

2. mv /etc/yum.repos.d/*.repo /etc/yum.repos.d/backup

3. yum clean all

4. rpm -ivh http://dl.fedoraproject.org/pub/epel/7/x86_64/e/epel-release-7-8.noarch.rpm --force

5. yum list all

In case if your OS is CentOS6 then run the following commands.

## Run these commands as root user

1. mkdir /etc/yum.repos.d/backup

2. mv /etc/yum.repos.d/*.repo /etc/yum.repos.d/backup

3. yum clean all

4. rpm -ivh http://download.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm --force

5. yum list all