Why does Yum return error: [Errno] No more mirrors to try?

https://access.redhat.com/solutions/203603

ISSUE

Yum update fails with the error: [Errno-] No more mirrors-try
Yum update fails with:-< Br>error downloading p Ackages:
Installmedia: [Errno] No more mirrors to try.
Yum fails with:
Error downloading Packages:
ftp-0.17-35.el5.x86_64:failure:ftp-0.17-35.el5.x86_64.rpm from Red5repo55:[errno [] No more mirrors to try. [[6]] "(code-1) Packages scheduled
Yum fails with:
Downloading Packages:
https://cdn.redhat.com/content/ DIST/RHEL/SERVER/6/6SERVER/X86_64/SUPPLEMENTARY/OS/PACKAGES/JAVA-1.6.0-IBM-1.6.0.15.0-1JPP.1.EL6_4.X86_64.RPM: [Errno 14] Pycurl ERROR-"The requested URL returned error:404 not Found"
Trying other mirror.
Error downloading Packages:
1:java-1.6.0-ibm-1.6.0.15.0-1jpp.1.el6_4.x86_64:failure:packages/ java-1.6.0-ibm-1.6.0.15.0-1jpp.1.el6_4.x86_64.rpm from Rhel-6-server-supplementary-rpms: [Errno) No more mirrors To try.
Environment

Red Hat Enterprise Linux 5 and later
Red Hat Network (portal)
Subscription Management (RHSM)
RESOLUTION

Check what files is present UNDER/ETC/YUM.REPOS.D directory by:-
# LL/ETC/YUM.REPOS.D
If the system is registered to the portal Classic, only Rhel-source.repo should be present under/etc/yum.repos.d/.
If the system is registered to Subscription-manager (RHSM), Rhel-source.repo and ' Redhat.repo ' are present.
If any local repositories, or any other media repositories is present, remove them by:-
# rm-rf/etc/yum.repos.d/<local or other repository name>
Remove old Yum cache from system by running following commands:
# rm-fr/var/cache/yum/*
# Yum Clean All
Check If you can list the valid repositories by:-
# yum Repolist
ROOT cause

This issue persist due to following reasons:
Corrupted Yum cache.
Inaccessibility of a repository URL from the system.
Presence of customized or other media repositories.
DIAGNOSTIC STEPS

Check the accessibility of the repository URL in the system/network.
# ping URL
Check the repositories UNDER/ETC/YUM.REPOS.D
Ll/etc/yum.repos.d
Collect a sosreport of the affected system.

Why does Yum return error: [Errno] No more mirrors to try?