yum error "Cannot retrieve metalink for repository: epel. Please verify its path and try again" updating ContextBroker

You just needed to update ca-certificates package. Before that just disable all repos with https that are failing. That's why solution with commenting mirrorlist or using http instead https would work also.

For example if you need to disable only epel repo:

yum --disablerepo=epel -y update  ca-certificates

This will also help wget, curl, and anything else that uses SSL certificates.

I solved this issue editing both /etc/yum.repos.d/epel.repo and /etc/yum.repos.d/epel-testing.repo files, commenting all entries starting with mirrorlist=... and uncommenting all the entries starting with baseurl=....

use this command:

sudo sed -i "s/mirrorlist=https/mirrorlist=http/" /etc/yum.repos.d/epel.repo

or alternatively use command

vi /etc/yum.repos.d/epel.repo

go to line number 4 and change the url from

mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=epel-6&arch=$basearch

to

mirrorlist=http://mirrors.fedoraproject.org/metalink?repo=epel-6&arch=$basearch