diff --git a/core/url_registry/tests.py b/core/url_registry/tests.py
index ff01b6bde..177d842e4 100644
--- a/core/url_registry/tests.py
+++ b/core/url_registry/tests.py
@@ -122,3 +122,11 @@ def test_post(self, lookup_mock):
         self.assertEqual(response.status_code, 200)
         self.assertEqual(response.data, RepoListSerializer(source).data)
         lookup_mock.assert_called_with('https://foo.com', source.organization)
+
+        response = self.client.post(
+            '/orgs/Foo/url-registry/$lookup/',
+            {'url': 'https://foo.com'},
+            HTTP_AUTHORIZATION=f'Token {token}'
+        )
+
+        self.assertEqual(response.status_code, 404)
diff --git a/core/url_registry/views.py b/core/url_registry/views.py
index 61aed8df0..3f5879e03 100644
--- a/core/url_registry/views.py
+++ b/core/url_registry/views.py
@@ -37,6 +37,9 @@ def set_parent_resource(self):
             self.parent_resource = UserProfile.objects.filter(username=user).first()
             self.parent_resource_type = 'user'
 
+        if (org or user) and not self.parent_resource:
+            raise Http404()
+
         self.kwargs['parent_resource'] = self.parent_resource
         self.kwargs['parent_resource_type'] = self.parent_resource_type