How to authenticate sellers using Stripe Connect & API Connector

Hello all,

I am trying to authenticate sellers using Stripe Connect & API connector, but i get the error “unexpected status code” or “token generation error” whenever I initialise the call. Anyone know what I am doing wrong??

Here are my settings:

documentation: Using Connect with Standard accounts | Stripe Documentation

I managed to get it working in POSTman, so it means there is something wrong with my API connector settings. Anyone able to assist?