horizon error

2015-07-13 13:35:19,964 5988 DEBUG openstack_dashboard.api.nova novaclient connection created using token "----" and url "http://172.16.1.81:8774/v2/----"
2015-07-13 13:35:19,966 5988 ERROR django.request Internal Server Error: /dashboard/admin/
Traceback (most recent call last):
  File "/usr/lib/python2.6/site-packages/django/core/handlers/base.py", line 109, in get_response
    response = callback(request, *callback_args, **callback_kwargs)
  File "/usr/lib/python2.6/site-packages/horizon/decorators.py", line 38, in dec
    return view_func(request, *args, **kwargs)
  File "/usr/lib/python2.6/site-packages/horizon/decorators.py", line 86, in dec
    return view_func(request, *args, **kwargs)
  File "/usr/lib/python2.6/site-packages/horizon/decorators.py", line 54, in dec
    return view_func(request, *args, **kwargs)
  File "/usr/lib/python2.6/site-packages/horizon/decorators.py", line 38, in dec
    return view_func(request, *args, **kwargs)
  File "/usr/lib/python2.6/site-packages/horizon/decorators.py", line 86, in dec
    return view_func(request, *args, **kwargs)
  File "/usr/lib/python2.6/site-packages/django/views/generic/base.py", line 48, in view
    return self.dispatch(request, *args, **kwargs)
  File "/usr/lib/python2.6/site-packages/django/views/generic/base.py", line 69, in dispatch
    return handler(request, *args, **kwargs)
  File "/usr/lib/python2.6/site-packages/horizon/tables/views.py", line 154, in get
    handled = self.construct_tables()
  File "/usr/lib/python2.6/site-packages/horizon/tables/views.py", line 145, in construct_tables
    handled = self.handle_table(table)
  File "/usr/lib/python2.6/site-packages/horizon/tables/views.py", line 118, in handle_table
    data = self._get_data_dict()
  File "/usr/lib/python2.6/site-packages/horizon/tables/views.py", line 181, in _get_data_dict
    self._data = {self.table_class._meta.name: self.get_data()}
  File "/usr/share/openstack-dashboard/openstack_dashboard/wsgi/../../openstack_dashboard/dashboards/admin/overview/views.py", line 60, in get_data
    data = super(GlobalOverview, self).get_data()
  File "/usr/share/openstack-dashboard/openstack_dashboard/wsgi/../../openstack_dashboard/usage/views.py", line 43, in get_data
    self.usage.summarize(*self.usage.get_date_range())
  File "/usr/share/openstack-dashboard/openstack_dashboard/wsgi/../../openstack_dashboard/usage/base.py", line 200, in summarize
    if not api.nova.extension_supported('SimpleTenantUsage', self.request):
  File "/usr/lib/python2.6/site-packages/horizon/utils/memoized.py", line 90, in wrapped
    value = cache[key] = func(*args, **kwargs)
  File "/usr/share/openstack-dashboard/openstack_dashboard/wsgi/../../openstack_dashboard/api/nova.py", line 752, in extension_supported
    extensions = list_extensions(request)
  File "/usr/lib/python2.6/site-packages/horizon/utils/memoized.py", line 90, in wrapped
    value = cache[key] = func(*args, **kwargs)
  File "/usr/share/openstack-dashboard/openstack_dashboard/wsgi/../../openstack_dashboard/api/nova.py", line 743, in list_extensions
    return nova_list_extensions.ListExtManager(novaclient(request)).show_all()
  File "/usr/lib/python2.6/site-packages/novaclient/v1_1/contrib/list_extensions.py", line 37, in show_all
    return self._list("/extensions", 'extensions')
  File "/usr/lib/python2.6/site-packages/novaclient/base.py", line 67, in _list
    _resp, body = self.api.client.get(url)
  File "/usr/lib/python2.6/site-packages/novaclient/client.py", line 487, in get
    return self._cs_request(url, 'GET', **kwargs)
  File "/usr/lib/python2.6/site-packages/novaclient/client.py", line 465, in _cs_request
    resp, body = self._time_request(url, method, **kwargs)
  File "/usr/lib/python2.6/site-packages/novaclient/client.py", line 439, in _time_request
    resp, body = self.request(url, method, **kwargs)
  File "/usr/lib/python2.6/site-packages/novaclient/client.py", line 410, in request
    **kwargs)
  File "/usr/lib/python2.6/site-packages/requests/api.py", line 49, in request
    response = session.request(method=method, url=url, **kwargs)
  File "/usr/lib/python2.6/site-packages/requests/sessions.py", line 461, in request
    resp = self.send(prep, **send_kwargs)
  File "/usr/lib/python2.6/site-packages/requests/sessions.py", line 573, in send
    r = adapter.send(request, **kwargs)
  File "/usr/lib/python2.6/site-packages/requests/adapters.py", line 415, in send
    raise ConnectionError(err, request=request)
ConnectionError: ('Connection aborted.', error(111, 'Connection refused'))