Try another means of setting url

jupyter/base/values/values.yaml

@@ -41,13 +41,13 @@ hub:
         def main():
             app = Application(
                 [
-                    ('/services/?', RefreshHandler),
+                    ('/services/refresh-token', RefreshHandler),
                     (r'.*', RefreshHandler),
                 ]
             )
 
             http_server = HTTPServer(app)
-            url = urlparse(os.environ['JUPYTERHUB_SERVICE_URL'])
+            url = urlparse(f'http://{os.environ["PROXY_API_SERVICE_HOST"]}:{os.environ["PROXY_API_SERVICE_PORT"]}')
 
             http_server.listen(url.port, url.hostname)