Sign in with Linkedin not working (giving issue's of invalid access token and blocked by CORS Origin)

Question

As I'm trying to integrate Linkedin API to get user's email to make a social sign in functionality in my project. Currently my project is working in react.js as frontend and node.js as backend.

I'm working in 'localhost:3000'.

For that I have created a App in Linked Developers section. From that I got my 'Client id' and 'Client Secret' key. And I also selected sign in with linkedin in products. Then I have integrated one package for react which helps me to sign with linkedin process. On clicking of that button it opens a popup which asks for linkedin signin. After that successfull sign in I get a code and state in response. When I enter that code for authorization it shows invalid access token. I tried to hit the API for authorization - "https://www.linkedin.com/oauth/v2/authorization. Then I hit the API - "https://api.linkedin.com/v2/me to get user profile but still getting the issue of "invalid access token".

I have read multiple documents and tried to integrate linkedin API in frontend as well as in backend too. But both side I'm getting error of CORS issue (Cross origin has blocked). or redirect_uri is not as per registered value. (I have entered multiple redirect_uri's in my linkedin app but none of them are working). or access token is not proper.

Please help me in this issue. I'm not getting why I'm having this error. What steps I have to follow Please guide me breifly.

I have tried to hit the API in multiple ways: postman, sample html file through AJAX, in react using its one of package, in php file using AJAX. But same issue in all.