Issue with Angular App Authorization and Zoho CRM

Issue with Angular App Authorization and Zoho CRM

I was searching for a way to build an Angular app that can send requests and receive responses from the Zoho CRM. I tried all the possibilities documented in Zoho CRM documentation but nothing worked for me:

Steps I followed:

  1. I registered the app on https://api-console.zoho.com/service as Client-based, Server-Based, Self-Client.

  2. I followed the documentation https://www.zoho.com/accounts/protocol/oauth/web-server-applications.html for each case (Client,server,Self).

  3. request the Authorization request to get the code and generate the tokens to get access to CRM API https://accounts.zoho.com/oauth/v2/auth?response_type=code&client_id=1000.GMB0YULZHJK411284S8I5GZ4CHUEX0&scope=AaaServer.profile.Read&redirect_uri=https://www.zylker.com/oauthredirect&prompt=consent

  4. I got the code in the redirected URL
    https://www.zylker.com/oauthredirect?code=1000.9c3a2a6a5362125efc9f7666224313b6.d44f4b5b63e71fc682cdf20c771efead&location=us

  5. generating a Token from the app failed, and any request was even after getting the token from the postman using the generated code from the URL above.

and always getting CORS policy issues, even though I added in the request header the "Access-Control-Allow-Origin":"*" or replacing the * with my origin: