I took all the possible steps to resolve it quickly.
initializing the unused iPhone and set the language and region to English / US.
After setting up VPN (US server), everything is done.
Install smartthings app, I try to login to my existing account --> Failed
Create a new smarthings account and login -> Success.(VPN!!!)
As a result, I think server location is important when creating a smartthings account.
When I log in with a new account on my current iPhone, the hub category looks OK.