Cors error with webapp on localhost "No 'Access-Control-Allow-Origin' header is present on the requested resource."

Hello,
I am trying to create a web app using React js to act as a dashboard to show the connect clients.
i have the client id and client secret to request a access token.
When i send the fetch request in java script i get the error:

i can successfully make the request using postman, or opening the webapp on Firefox and disabling Cors,
but this is not ideal.

is there a fix for this? i have looked on the forums and only found 2 relevant posts from 1 and 2 years ago with no clear solution

thanks in advance
Brendan