`[Errno 14] Peer cert cannot be verified or peer cert invalid` while executing yum update.

Issue

• yum update fails with below error :

http://cdn.redhat.com/content/dist/rhel/server/6/6Server/x86_64/os/repodata/repomd.xml: [Errno 14] Peer cert cannot be verified or peer cert invalid
Trying other mirror.
It was impossible to connect to the Red Hat servers.
This could mean a connectivity issue in your environment, such as the requirement to configure a proxy,
or a transparent proxy that tampers with TLS security, or an incorrect system clock.
Please collect information about the specific failure that occurs in your environment,
using the instructions in: https://access.redhat.com/solutions/1527033 and open a ticket with Red Hat Support.

Error: Cannot retrieve repository metadata (repomd.xml) for repository: rhel-6-server-rpms. Please verify its path and try again