@pfaffman I do not understand your response, it does not contain an answer. That topic shows how to find out about endpoints that are not documented. This one is, and it is one of the very few API calls that cannot be reverse engineered like that, since this specific API endpoint is never called by the Ember frontend ?
@mpemburn it should work, the documentation looks correct. The external ID is the ID in your remote database, which is passed when you have SSO enabled. Can you share your code?