try without external

plugins/unity_integration.py

@@ -33,7 +33,7 @@ class UnityIntegrationView(AppBuilderBaseView):
     @unity.route('/')
     @unity.route('/login')
     def login():
-        redirect_uri = url_for('unity.authorize', _external=True)
+        redirect_uri = url_for('unity.authorize')
         log.debug("Redirect uri is " + str(redirect_uri))
         return oauth.unity.authorize_redirect(redirect_uri)