Node.js - Error: Cannot find module './setuppassport'

I'm new to Node.js and I followed a certain tutorial to start and make a simple website but I'm getting an error after trying to open the page on address localhost:3000. It was working just fine so far but after I added some code in app.js I'm getting this terminal error:

` node:internal/modules/cjs/loader:936
  throw err;
  ^

Error: Cannot find module './setuppassport'
Require stack:
- C:\Users\Natasa\Desktop\nodejsapp\app.js
    at Function.Module._resolveFilename (node:internal/modules/cjs/loader:933:15)
    at Function.Module._load (node:internal/modules/cjs/loader:778:27)       
    at Module.require (node:internal/modules/cjs/loader:999:19)
    at require (node:internal/modules/cjs/helpers:102:18)
    at Object.<anonymous> (C:\Users\Natasa\Desktop\nodejsapp\app.js:11:21)   
    at Module._compile (node:internal/modules/cjs/loader:1097:14)
    at Object.Module._extensions..js (node:internal/modules/cjs/loader:1149:10)
    at Module.load (node:internal/modules/cjs/loader:975:32)
    at Function.Module._load (node:internal/modules/cjs/loader:822:12)       
    at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:81:12) {
  code: 'MODULE_NOT_FOUND',
  requireStack: [ 'C:\\Users\\Natasa\\Desktop\\nodejsapp\\app.js' ]
}

Node.js v17.3.0
[nodemon] app crashed - waiting for file changes before starting... 

The app.js code:

var express = require("express");
var path = require("path");
var mongoose = require("mongoose");
var bodyParser = require("body-parser");
var cookieParser = require("cookie-parser");
var passport = require("passport");
var session = require("express-session");
var flash = require("connect-flash");
var params = require("./params/params");

var setUpPassport = require("./setuppassport");
//var routes = require("./routes");

var app = express();
mongoose.connect(params.DATABASECONNECTION, {useUnifiedTopology:true, useNewUrlParser:true, useCreateIndex:true});
setUpPassport();

app.set("port", process.env.PORT || 3000);
app.set("views", path.join(__dirname, "views"));
app.set("view engine", "ejs");
app.use(bodyParser.urlencoded({extended:false}));
app.use(cookieParser());
app.use(session({
    secret:"doemlfgddfsoi!gjdsf5684561dsf",
    resave:false,
    saveUninitialized:false
}));

app.use(passport.initialize());
app.use(passport.session());
app.use(flash());

app.use("/", require("./routes/web"));
app.use("/api", require("./routes/api"));

app.listen(app.get("port"), function(){
    console.log("Server started on port " + app.get("port"));
}) 

I see that the error is around the var setUpPassport = require("./setuppassport"); line but I'm not sure how to fix or what the problem is. Any tips or possible solutions?