According to the "Authorize user" API document, the "state" may contain a "custom string of your choice."
Recently we find out that if sending the request with "ip" like parameters in URL, we will get 403 forbidden. For example:
https://account.box.com/api/oauth2/authorize?response_type=code&state=http://8.8.8.8
We need the IP-like in parameter to identify and verify a user on redirect.
Please help check this issue. Thank you!