subscription-manager command fails with error -"dbus.exceptions.DBusException: org.freedesktop.DBus.Error.NoReply: Did not receive a reply."

Issue

• "subscription-manager" command fails with below error:-

# subscription-manager attach --auto

Installed Product Current Status:
Product Name: Red Hat Enterprise Linux for x86_64
Status:       Not Subscribed

Unable to find available subscriptions for all your installed products.
ERROR:dbus.proxies:Introspect error on :1.9009:/EntitlementStatus: dbus.exceptions.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.
ERROR:subscription_manager.dbus_interface: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/python3.6/site-packages/subscription_manager/dbus_interface.py", line 66, in _update
    ignore_reply=self.has_main_loop)
  File "/usr/lib64/python3.6/site-packages/dbus/proxies.py", line 70, in __call__
    return self._proxy_method(*args, **keywords)
  File "/usr/lib64/python3.6/site-packages/dbus/proxies.py", line 145, in __call__
    **keywords)
  File "/usr/lib64/python3.6/site-packages/dbus/connection.py", line 651, in call_blocking
    message, timeout)
dbus.exceptions.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.