Hi @Valdinia, Welcome to Community!
It seems the endpoint which you are trying to use has CORS policy enabled. You need to pass headers like the one mentioned “Access-Control-Allow-Origin” in your error message.
Generally postman includes these headers by default. To verify this you can check for hidden or auto populated headers under header tab in postman else you can also find in postman console what all headers were sent in the request payload.
If policy is there you may need to pass extra headers to align with CORS policy in your JS script from wordpress.
Hope this helps 