Wix Headless: Error while creating auth code for oauth

Question:
I am having error 404 when I’m trying to generate auth code for oauth.

Product:
Wix Developer

What are you trying to achieve:
I want to use wix headless api for login purpose, when I’m trying to generate auth code it’s showing 404 page.

What have you already tried:
I have already created custom app, generated token, app id and app secret