mock fails in rhel7 system

Hallo,

I'm trying to use mock in rhel 7 distribution and I'm getting the following error during chroot initialization:

mock -r rhel-7-x86_64 --init
INFO: mock.py version 1.4.3 starting (python version = 2.7.5)...
Start: init plugins
INFO: selinux disabled
Finish: init plugins
Start: run
Start: clean chroot
Finish: clean chroot
Start: chroot init
INFO: calling preinit hooks
INFO: enabled root cache
INFO: enabled yum cache
Start: cleaning yum metadata
Finish: cleaning yum metadata
INFO: enabled HW Info plugin
Mock Version: 1.4.3
INFO: Mock Version: 1.4.3
Start: yum install
Failed to set locale, defaulting to C
https://cdn.redhat.com/content/dist/rhel/server/7/7/x86_64/optional/os/repodata/repomd.xml: [Errno 14] HTTPS Error 404 - Not Found
Trying other mirror.
To address this issue please refer to the below knowledge base article

This system has rhel7 self-support subscription. Does this error mean that I cannot install packages in chroot on the same system?

rhel-7-x86_64.cfg I created myself from existing epel-7-x86_64.cfg. Just in case I attach it here.

best regards,