API avatar URL and SSO avatar URL are different

I am current getting user information in two different ways:

SSO provides a URL to avatar like this:
https://cdn.WEBSITE.COM/original/1X/42270b70f2cbcfd168082aa6be55cf98d5b387bf.jpeg

I can not get that same one with the API, as API using user/{username}.json makes it:
/user_avatar/www.WEBSITE.COM/{username}/{size}/162_2.png

How can I get the one SSO offers, as I have a subdomain associated to it, and my images are on CDN.

Thanks.