An "error_access_from_ip_not_allowed" error when call API

Hello.
We have developed an app that call API to get access token with this(https://developer.box.com/reference/post-oauth2-token/)

And we got an error [error_access_from_ip_not_allowed].

I referenced [https://support.box.com/hc/en-us/community/posts/4407014937107-An-error-access-from-ip-not-allowed-error-when-a-user-log-in?input_string=error_access_from_ip_not_allowed#comment-overview] and I think I met the same problem and I need to ask support team to add IP to IP allow list.

Can I get a sample or manual of how to request add IP to the Support team?

Thanks