Access to "subscription.rhsm.redhat.com" occurred and error when unregistering a client registered on the satellite server.

Issue

Access to "subscription.rhsm.redhat.com" occurred and error when unregistering a client registered on the satellite server.
It seems that unregister can be executed, but how to prevent the error from being output?

Step:

# subscription-manager register --org="org" --activationkey="key"
# subscription-manager list
# subscription-manager status
# subscription-manager unregister

/var/log/rhsm/rhsm.log

[ERROR] subscription-manager:5850:MainThread @dbus_interface.py:70 - org.freedesktop.DBus.Error.NoReply: Did not receive a reply. Possible causes include: the remote application did not send a reply, the message bus security policy blocked the reply, the reply timeout expired, or the network connection was broken.
Traceback (most recent call last):
  File "/usr/lib64/python2.7/site-packages/subscription_manager/dbus_interface.py", line 66, in _update
    ignore_reply=self.has_main_loop)
  File "/usr/lib64/python2.7/site-packages/dbus/proxies.py", line 70, in __call__
    return self._proxy_method(*args, **keywords)
  File "/usr/lib64/python2.7/site-packages/dbus/proxies.py", line 145, in __call__
    **keywords)
  File "/usr/lib64/python2.7/site-packages/dbus/connection.py", line 651, in call_blocking
    message, timeout)
DBusException: org.freedesktop.DBus.Error.NoReply: Did not receive a reply. Possible causes include: the remote application did not send a reply, the message bus security policy blocked the reply, the reply timeout expired, or the network connection was broken.