Shopify APP Installation

[MiguelSantillan]

I have been following the guide: https://shopify.dev/tutorials/build-a-shopify-app-with-node-and-react/
but I have a problem when installing the app, I get this error 

Internal Server Error

this is the error that appears in the npm:

TypeError [ERR_INVALID_ARG_TYPE]: The "key" argument must be of type string or an instance of Buffer, TypedArray, DataView, or KeyObject. Received undefined
at prepareSecretKey (internal/crypto/keys.js:304:11)
at new Hmac (internal/crypto/hash.js:113:9)
at Object.createHmac (crypto.js:143:10)
at sign (C:\Users\mikil\Documents\sample-embedded-app\node_modules\keygrip\index.js:23:8)
at Keygrip.sign (C:\Users\mikil\Documents\sample-embedded-app\node_modules\keygrip\index.js:30:38)
at Cookies.set (C:\Users\mikil\Documents\sample-embedded-app\node_modules\cookies\index.js:110:30)
at oAuthStart (C:\Users\mikil\Documents\sample-embedded-app\node_modules\@shopify\koa-shopify-auth\dist\src\auth\create-oauth-start.js:18:21)
at C:\Users\mikil\Documents\sample-embedded-app\node_modules\@shopify\koa-shopify-auth\dist\src\auth\index.js:54:46
at step (C:\Users\mikil\Documents\sample-embedded-app\node_modules\tslib\tslib.js:141:27)
at Object.next (C:\Users\mikil\Documents\sample-embedded-app\node_modules\tslib\tslib.js:122:57)

 ngrok :

GET /auth 500 Internal Server Error

GET /favicon.ico 302 Found

GET /auth 500 Internal Server Error

GET / 302 Found

GET /auth 500 Internal Server Error

GET /favicon.ico 302 Found

GET /auth 500 Internal Server Error

GET /auth 500 Internal Server Error

GET /favicon.ico 302 Found

GET /auth 500 Internal Server Error

server.js:

require('isomorphic-fetch');
const dotenv = require('dotenv');
const Koa = require('koa');
const next = require('next');
const { default: createShopifyAuth } = require('@shopify/koa-shopify-auth');
const { verifyRequest } = require('@shopify/koa-shopify-auth');
const session = require('koa-session');

dotenv.config();

const port = parseInt(process.env.PORT, 10) || 3000;
const dev = process.env.NODE_ENV !== 'production';
const app = next({ dev });
const handle = app.getRequestHandler();

const { SHOPIFY_API_SECRET_KEY, SHOPIFY_API_KEY } = process.env;
app.prepare().then(() => {
const server = new Koa();
server.use(session({ secure: true, sameSite: 'none' }, server));
server.keys = [SHOPIFY_API_SECRET_KEY];
server.use(
createShopifyAuth({
apiKey: SHOPIFY_API_KEY,
secret: SHOPIFY_API_SECRET_KEY,
scopes: ['read_products'],
afterAuth(ctx) {
const { shop, accessToken } = ctx.session;
ctx.redirect('/');
},
}),
);

server.use(verifyRequest());

server.use(async (ctx) => {
await handle(ctx.req, ctx.res);
ctx.respond = false;
ctx.res.statusCode = 200;
return
});
server.listen(port, () => {
console.log(`> Ready on http://localhost:${port}`);
});
});

I have already done putting "set" before the lines in my .env file. I also have two .env files, one with a name and one without a name