POST /oauth/authorize

The old URL for OAuth authorize is https://{tenant}.identitynow.com/oauth/authorize

This has been replaced by https://{tenant}.login.sailpoint.com/oauth/authorize as described in the authentication guide. The difference here is the inclusion of login in the hostname.

https://developer.sailpoint.com/idn/api/authentication/#request-access-token-with-authorization-code-grant-flow