Flask app: CORS header ‘Access-Control-Allow-Origin’ missing, having cors() enabled,and many requests goes through

Hi,when my request is for little data,i have no errors and status 200,but when i do requests that responds more data -> yahoo finance does more requests,i get the CORS error. This is the api url https://jjtrading-yzukr.ondigitalocean.app/api/minsmax?days_back=2d&coins_quantity=2 ,when i request little coins (2) its no problem,but if i request: https://jjtrading-yzukr.ondigitalocean.app/api/minsmax?days_back=2d&coins_quantity=50 (50 coins) ,i get the CORS error. Here is my flask app:

from utils import *
from flask_cors import CORS, cross_origin
from flask import Flask, request, jsonify

app = Flask(__name__)
cors = CORS(app)

@app.route('/')
@cross_origin()
def index():
    return "Home"

@app.route('/api', methods=['GET'])
@cross_origin()
def api():
    return{
        "tutorial": "Flask React Herokuu"
    }

@app.route('/api/minsmax', methods=['GET'])
@cross_origin(headers=['Content-Type', 'Authorization'])
def prices():
    days_back = request.args.get('days_back')
    coins_quantity = request.args.get('coins_quantity')
    response = jsonify(get_coins_in_min_max(days_back, coins_quantity))
    return response


@app.route('/api/minsmax/coinsexcluded', methods=['GET'])
@cross_origin()
def coins_excluded():
    return json.dumps(coins_exceptions)


@app.route('/api/minsmax/addcoin/', methods=['PUT'], strict_slashes=False)
@cross_origin()
def add_coin():
    coin = request.args.get('coin')
    coins_exceptions.append(coin)
    response = json.dumps(coins_exceptions)

    return response


if __name__ == '__main__':
    app.run()

Any idea what can be the issue? thanks!