Version 4.1.9 throws an error: "name": "ApplicationError", "message": "Email already taken" via Postman - strapi

Question

My System information
Node.js version: v16.13.0
NPM version: 8.1.0
Strapi version: 4.1.9
Database: Postgres
Operating system: MacOS
The Issue
I recently setup an instance of Strapi and Postgres via railway (https://railway.app), and tried making a few request to test the api. Upon making POST request to fetch/ update a user that was originally setup through Strapi admin, I am getting an Email already taken 404 error message.
Screenshots
https://freeimage.host/i/HCvcw0P
Steps to reproduce the behavior
Configured user Content-Type by adding a user_role field via Strapi admin (Note that this is not meant to replace the default Strapi user role).
Saved the file, and the entry was successfully saved in the database.
Made a GET Request to https://my-railway-url/api/users to retrieve ALL USERS successfully.
I made a Post request to https://my-railway-url/api/auth/local to get user info along with the JWT token
Received a JWT token along with user information.
Copied the JWT Token and made another POST request - with body set to JSON, entered info to update the existing user
Got an error Email already taken
Expected behavior
User information updated with the new entries.

Answer 1

the strapi user-permissions plugin, has it's own logic of controllers, with would not be the same as standard content-type api's
to use it you have following routes:
// LOGIN
url: `api/auth/local`
method: POST
body: {
identifier: string
password: string
}
// ME get current authenticated user
url: `api/users/me` // you can add '?populate=*' here
method: GET
// UPDATE USER
url: `api/users/:id` // you can add '?populate=*' here
method: POST
body: {
...data // < user data
}
seems ?id=3 is invalid in your query, should be /api/users/3