Failed to retrieve group file for repository when running yum command.

Issue

• yum update command fails with an error.

[root@satellite ~]# yum update
Loaded plugins: product-id, rhnplugin, search-disabled-repos
This system is receiving updates from RHN Classic or Red Hat Satellite.
rhel-x86_64-server-7/group                                                                                                                                            | 636 kB  00:00:00     
Failed to retrieve group file for repository: rhel-x86_64-server-7
No packages marked for update