Registering client host to Red Hat Satellite fails with HTTP error (400 - Bad Request): Problem creating unit class ConsumerDTO.

Issue

• Registering the host to the Red Hat Satellite server using the subscription-manager register or activation key command fails with the following error:

  # subscription-manager register or subscription-manager --org=Org_1 --activationkey=AK_1
  Problem creating unit class ConsumerDTO {
  created: null
  updated: null
  id: null
  uuid: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
  name: hostname
  username: foreman_admin
  entitlementStatus: null
  serviceLevel:
  role:
  usage:
  addOns: []
  .
  .
  

• Registering the host to the Red Hat Satellite server using the curl command failed with the following error:

  Problem creating unit class ConsumerDTO {
  created: null
  updated: null
  id: null
  .
  .
  .
  .
  } (HTTP error code 400: Bad Request)
  This system is not yet registered. Try 'subscription-manager register --help' for more information.
  ERROR: not_found
  Host was not found by the subscription UUID: '', this can happen if the host is registered already, but not to this instance