I have developed a rest api in Flask. All my api endpoints work fine when I test them with postman.

Now, I am developing an application with Javascript that consumes the resources of my api.

I'm having trouble consuming an endpoint that works with the delete method. Endpoints with get and post work fine, but not the delete method. I get the next CORS error:

Access to fetch at 'http://localhost:5000/contacto' from origin 'null' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: The value of the 'Access-Control-Allow-Origin' header in the response must not be the wildcard '*' when the request's credentials mode is 'include'.

This is my Javascript code:

let data ={id: id};
let url = "http://localhost:5000/contacto";
fetch(url, {
    credentials: 'include',
    method: 'DELETE',
    headers: {
        'Content-Type': 'application/json'
    },
    body: JSON.stringify(data)
})
.then(res => res.json())
.then(res => {
    alert(res.result);
});

On the server side, I use flask_cors. I configure the app with this code:

from flask import Flask, jsonify, request
from flask_cors import CORS

import controllers.userController as userController

app = Flask(__name__)
app.config['CORS_HEADERS'] = 'Content-Type'
#CORS(app)
#CORS(app, resources={r"/*": {"origins": "*"}}, send_wildcard=True)
 CORS(app, resources={r"/*": {"origins": "http://127.0.0.1:5500"}}) 

The path of my service with delete method is this:

@app.route('/contacto', methods = ['DELETE'])
def deleteContacto():
  parametros = request.args
  id = parametros['id']
  result = contactController.eliminar_contacto(id)

 response = None
if result == True:
    response = jsonify({'result':'Contacto eliminado con éxito'})
else:
    response = jsonify({'result':'Error al eliminar el contacto'})
response.headers.add('Access-Control-Allow-Methods', 'GET,POST,PUT,DELETE,OPTIONS')
return response

I need some help. I have searched and tried many possible solutions but they do not work for me. I'm a bit desperate.

Thanks in advance and regards.