web application 404, http://localhost:3001/

[hhniao]

first time visit: http://localhost:3001/, will be return 404.
open http://localhost:3001/en, will rewrite to http://localhost:3001/ and return 200.

1, http://localhost:3001/en -> http://localhost:3001/ return 200, no any problem.
2, http://localhost:3001/ return 200, no any problem
3, clean cookies, session, localstorage
4, http://localhost:3001/ return 404