Enable POST wordpress / woocommerce method

I'm trying to send a POST to woocommerce / wordpress using the woocommerce-api API, but only I get the error 401 that says:

  

Fetch API can not load link ... Response for preflight has invalid HTTP status code 401

     

TypeError: Failed to fetch at TypeError (native)

I have already tried to add permission via htaccess with:

<IfModule mod_headers.c>
    Header add Access-Control-Allow-Origin: "http://localhost:3000"
    Header add Access-Control-Allow-Methods: "GET,POST,OPTIONS,DELETE,PUT"
    Header add Access-Control-Allow-Headers: "Content-Type"
    Header add Access-Control-Allow-Credentials: "true"
</IfModule>

I also tried right in header.php of my theme:

header("Access-Control-Allow-Origin: *");

And also in the file functions.php :

header("Access-Control-Allow-Origin: *");
header("Access-Control-Allow-Methods: *");

POST is being performed from a REACT plication application through the local server that is made available through react-scripts start

When I click on the link provided by the error I get the following JSON :

{"code":"woocommerce_rest_authentication_error","message":"Assinatura inv\u00e1lida - a assinatura fornecida n\u00e3o corresponde.","data":{"status":401}}

The API keys already have permission and read and write.