Identity endpoint returns only the user_id field for a live app

[ACLayer]

Hi,

I'm using the identity API with auth token for a live app.
When I make a call to:  https://api-m.paypal.com/v1/identity/oauth2/userinfo?schema=paypalv1.1, I'm just receiving the 
user_id field instead of all the fields mentioned in the documentation here.

Am I missing something?
Appreciate your input. Thank you in advance!