question about use cloud identity service User Registration Service API

    I want to test how to use the hana cloud identity service User Registration Service API to create user, when I send following url

https://x47bf8fc8.accounts400.ondemand.com/service/users?name_id=1196612589_qq&email=1196612589@qq.com&spCustomAttribute1=vendor_001&sp_name=S2f854794-96d6-40eb-a5fc-0420f9f26544

it will return 401Unauthorized   “Service provider cannot be determined for this request”,   how to give the service provider information? By the sp_name?  And from where to get the unique id for service provider?