diff --git a/releasenotes/notes/bug-1754514-ca6ebe16c4e4b3b0.yaml b/releasenotes/notes/bug-1754514-ca6ebe16c4e4b3b0.yaml
new file mode 100644
index 00000000..e8e6f8a8
--- /dev/null
+++ b/releasenotes/notes/bug-1754514-ca6ebe16c4e4b3b0.yaml
@@ -0,0 +1,5 @@
+---
+critical:
+  - |
+    Fixes authentication failure when SessionService attribute is
+    not present in the root resource.
diff --git a/sushy/main.py b/sushy/main.py
index ec178225..b0a4334d 100644
--- a/sushy/main.py
+++ b/sushy/main.py
@@ -16,6 +16,7 @@ import logging
 
 from sushy import auth as sushy_auth
 from sushy import connector as sushy_connector
+from sushy import exceptions
 from sushy.resources import base
 from sushy.resources.manager import manager
 from sushy.resources.sessionservice import session
@@ -36,14 +37,13 @@ class Sushy(base.ResourceBase):
     uuid = base.Field('UUID')
     """The Redfish root service UUID"""
 
-    _systems_path = base.Field(['Systems', '@odata.id'], required=True)
+    _systems_path = base.Field(['Systems', '@odata.id'])
     """SystemCollection path"""
 
-    _managers_path = base.Field(['Managers', '@odata.id'], required=True)
+    _managers_path = base.Field(['Managers', '@odata.id'])
     """ManagerCollection path"""
 
-    _session_service_path = base.Field(['SessionService', '@odata.id'],
-                                       required=True)
+    _session_service_path = base.Field(['SessionService', '@odata.id'])
     """SessionService path"""
 
     def __init__(self, base_url, username=None, password=None,
@@ -96,6 +96,10 @@ class Sushy(base.ResourceBase):
             not found
         :returns: a SystemCollection object
         """
+        if not self._systems_path:
+            raise exceptions.MissingAttributeError(
+                attribute='Systems/@odata.id', resource=self._path)
+
         return system.SystemCollection(self._conn, self._systems_path,
                                        redfish_version=self.redfish_version)
 
@@ -115,6 +119,10 @@ class Sushy(base.ResourceBase):
             not found
         :returns: a ManagerCollection object
         """
+        if not self._managers_path:
+            raise exceptions.MissingAttributeError(
+                attribute='Managers/@odata.id', resource=self._path)
+
         return manager.ManagerCollection(self._conn, self._managers_path,
                                          redfish_version=self.redfish_version)
 
@@ -130,9 +138,14 @@ class Sushy(base.ResourceBase):
     def get_session_service(self):
         """Get the SessionService object
 
-        :raises: MissingAttributeError, if the collection attribue is not found
+        :raises: MissingAttributeError, if the collection attribute is
+            not found
         :returns: as SessionCollection object
         """
+        if not self._session_service_path:
+            raise exceptions.MissingAttributeError(
+                attribute='SessionService/@odata.id', resource=self._path)
+
         return sessionservice.SessionService(
             self._conn, self._session_service_path,
             redfish_version=self.redfish_version)
diff --git a/sushy/tests/unit/json_samples/bare_minimum_root.json b/sushy/tests/unit/json_samples/bare_minimum_root.json
new file mode 100644
index 00000000..1f558141
--- /dev/null
+++ b/sushy/tests/unit/json_samples/bare_minimum_root.json
@@ -0,0 +1,11 @@
+{
+    "@odata.type": "#ServiceRoot.v1_0_2.ServiceRoot",
+    "Id": "RootService",
+    "Name": "Root Service",
+    "RedfishVersion": "1.0.2",
+    "UUID": "92384634-2938-2342-8820-489239905423",
+    "Oem": {},
+    "@odata.context": "/redfish/v1/$metadata#ServiceRoot",
+    "@odata.id": "/redfish/v1/",
+    "@Redfish.Copyright": "Copyright 2014-2016 Distributed Management Task Force, Inc. (DMTF). For the full DMTF copyright policy, see http://www.dmtf.org/about/policies/copyright."
+}
diff --git a/sushy/tests/unit/test_main.py b/sushy/tests/unit/test_main.py
index 362cbb4b..8b1a969b 100644
--- a/sushy/tests/unit/test_main.py
+++ b/sushy/tests/unit/test_main.py
@@ -19,6 +19,7 @@ import mock
 
 from sushy import auth
 from sushy import connector
+from sushy import exceptions
 from sushy import main
 from sushy.resources.manager import manager
 from sushy.resources.sessionservice import session
@@ -117,3 +118,30 @@ class MainTestCase(base.TestCase):
         mock_sess.assert_called_once_with(
             self.root._conn, 'asdf',
             redfish_version=self.root.redfish_version)
+
+
+class BareMinimumMainTestCase(base.TestCase):
+
+    def setUp(self):
+        super(BareMinimumMainTestCase, self).setUp()
+        self.conn = mock.MagicMock()
+        with open('sushy/tests/unit/json_samples/'
+                  'bare_minimum_root.json', 'r') as f:
+            self.conn.get.return_value.json.return_value = json.loads(f.read())
+        self.root = main.Sushy('http://foo.bar:1234', verify=True,
+                               auth=mock.MagicMock(), connector=self.conn)
+
+    def test_get_system_collection_when_systems_attr_absent(self):
+        self.assertRaisesRegex(
+            exceptions.MissingAttributeError,
+            'Systems/@odata.id', self.root.get_system_collection)
+
+    def test_get_manager_collection_when_managers_attr_absent(self):
+        self.assertRaisesRegex(
+            exceptions.MissingAttributeError,
+            'Managers/@odata.id', self.root.get_manager_collection)
+
+    def test_get_session_service_when_sessionservice_attr_absent(self):
+        self.assertRaisesRegex(
+            exceptions.MissingAttributeError,
+            'SessionService/@odata.id', self.root.get_session_service)