Hi Tienbao,
I tested the AppWarpCocos2dx SDK using Cocos2d-x v3.5 on Simulator as well iPhone 5S and it is working fine. I am listing here the possible reasons of auth_error:
1. Trying to connect with a user name which is already connected on some other device. Try to connect with unique user name and see if it works.
2. Trying to connect with wrong keys.
Please verify once and let us know. If that is not the case, then you can share a sample source code so that we can find out what is the problem.
Thanks.