subscription-manager commands fails with error "rhsm.utils.ServerUrlParseErrorPort".

Issue

• When trying to register a system with subscription-manager the error rhsm.utils.ServerUrlParseErrorPort is encountered:-

  # subscription-manager identity
  Traceback (most recent call last):
    File "/usr/sbin/subscription-manager", line 9, in <module>
      load_entry_point('subscription-manager==1.24.52', 'console_scripts', 'subscription-manager')()
    File "/usr/lib64/python2.7/site-packages/subscription_manager/scripts/subscription_manager.py", line 86, in main
      return managercli.ManagerCLI().main()
    File "/usr/lib64/python2.7/site-packages/subscription_manager/managercli.py", line 3181, in __init__
      CLI.__init__(self, command_classes=commands)
    File "/usr/lib64/python2.7/site-packages/subscription_manager/cli.py", line 101, in __init__
      cmd = clazz()
    File "/usr/lib64/python2.7/site-packages/subscription_manager/managercli.py", line 1642, in __init__
      attr='addons', commands=['unset', 'add', 'remove'])
    File "/usr/lib64/python2.7/site-packages/subscription_manager/managercli.py", line 611, in __init__
      self.store = self._get_synced_store()
    File "/usr/lib64/python2.7/site-packages/subscription_manager/managercli.py", line 646, in _get_synced_store
      uep = inj.require(inj.CP_PROVIDER).get_consumer_auth_cp()
    File "/usr/lib64/python2.7/site-packages/subscription_manager/cp_provider.py", line 110, in get_consumer_auth_cp
      restlib_class=self.restlib_class)
    File "/usr/lib64/python2.7/site-packages/rhsm/connection.py", line 836, in __init__
      info = utils.get_env_proxy_info()
    File "/usr/lib64/python2.7/site-packages/rhsm/utils.py", line 225, in get_env_proxy_info
      info = parse_url(proxy_info, default_port=DEFAULT_PROXY_PORT)
    File "/usr/lib64/python2.7/site-packages/rhsm/utils.py", line 201, in parse_url
      raise ServerUrlParseErrorPort(local_server_entry)
  rhsm.utils.ServerUrlParseErrorPort