Yum commands show warnings "Repo <rhel_reponame>; forced skip_if_unavailable=True due to: /etc/pki/entitlement/xxx-key.pem"

Issue

When running yum commands like yum repolist, yum update etc show warnings due to being unable to read <xxx>-key.pem file in /etc/pki/entitlement directory:

$ yum repolist
Loaded plugins: langpacks, product-id, search-disabled-repos, subscription-manager
Repo rhel-7-desktop-rpms forced skip_if_unavailable=True due to: /etc/pki/entitlement/<xxx>-key.pem
Repo rhel-7-desktop-rh-common-rpms forced skip_if_unavailable=True due to: /etc/pki/entitlement/<xxx>-key.pem
Repo rhel-7-desktop-optional-rpms forced skip_if_unavailable=True due to: /etc/pki/entitlement/<xxx>-key.pem
Repo rhel-7-desktop-extras-rpms forced skip_if_unavailable=True due to: /etc/pki/entitlement/<xxx>-key.pem
[...]