I've been trying to create a react web app for a few days now for my internship and I've encountered a CORS error. I am using the latest version of reactJS, and placing this in the create-react-app , and below is the code for fetching:

componentDidMount() {
  fetch('--------------------------------------------',{
    method: "GET",
    headers: {
      "access-control-allow-origin" : "*",
      "Content-type": "application/json; charset=UTF-8"
    }})
  .then(results => results.json())
  .then(info => {
    const results = info.data.map(x => {
      return {
        id: x.id,
        slug: x.slug,
        name: x.name,
        address_1: x.address_1,
        address_2: x.address_2,
        city: x.city,
        state: x.state,
        postal_code: x.postal_code,
        country_code: x.country_code,
        phone_number: x.phone_number,
      }
    })
    this.setState({warehouses: results, lastPage: info.last_page});
  })
  .then(console.log(this.state.warehouses))
 }

I'm sorry that I can't post the url for the API due to company rules, however, it is confirmed that there are no CORS setting in the API backend.
However, I encounter the following errors when run on mozilla

Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at ------------------. (Reason: CORS header ‘Access-Control-Allow-Origin’ missing).

and

Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at ---------------------------------------------. (Reason: CORS request did not succeed).

If run on chrome it gives the following error

Failed to load resource: the server responded with a status of 405 (Method Not Allowed)

and

Failed to load --------------------------------------------------------: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:3000' is therefore not allowed access. The response had HTTP status code 405. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disabled.

and

Uncaught (in promise) TypeError: Failed to fetch

Another thing is that I am able to open the url in my browsers with no problems or whatsoever.
Please help and thanks!

Additional Information

The reason I added the CORS setting is because it gives a CORS error, so removing it does not really solve the issue.
Next I tried to perform proxy setting, however, it now gives

Unhandled Rejection (SyntaxError): Unexpected token < in JSON at position 0

According to the internet this is caused becasue the response is not a JSON. However when I checked the API it gives this
api img
which means that return type should be a JSON right?

Additional Info

checking the respond will yield this
{"status":200,"total":1,"per_page":3,"current_page":1,"last_page":1,"next_page_url":null,"prev_page_url":null,"from":1,"to":3,"data":[{"id":1,"slug":"america","name":"america","address_1":"USA Court","address_2":"USA","city":"USA","state":"USA","postal_code":"94545","country_code":"US","phone_number":"10000001","created_by":null,"updated_by":null,"created_at":"2017-11-10 11:30:50+00","updated_at":"2018-06-28 07:27:55+00"}]}