Finding the Login URL for a Student

[LeeJonesMtSAC]

I'm trying to identify the login URL for a student so I can automatically email them the message "click here to login with your username and password."

Why don't I just send everybody our login? Not all of our students login via our college. Because we have both "home" students (enrolled directly) and "external" students (enrolled via the exchange i.e. CVC-OEI). Students from other colleges that take our courses must login to Canvas at their home college login URL.

In the attached screenshot, there's a second login ID from a different district. The primary email is also not our domain (doesn't contain mtsac.edu). This is our indication that the student is a CVC-OEI student, and they must login via their "home college" URL to access our sources. I need to find the login URL.

I can use either of these commands to get the user "profile" but not the login URL:

curl -H "Authorization: <token>" https://mtsac.instructure.com/api/v1/users/sis_user_id:A01234560
curl -H "Authorization: <token>" https://mtsac.instructure.com/api/v1/accounts/1/users?search_term=A01234560 

The section with the Login Info matches this API command. I can use the "account_id" to identify an external Canvas instance, but not the login URL:

curl -H "Authorization: <token>" "https://mtsac.instructure.com/api/v1/users/1200249913/logins"

I tried to look up the account ID, but even as a Canvas Admin for my college, I get the message:

{"status":"unauthorized","errors":[{"message":"user not authorized to perform that action"}]}

Thoughts?