Express. Failed to load resource: the server responded with a status of 404 - api

Question

I am trying to make a post request using router.post and I keep getting " the server responded with a status of 404.
I have a routes folder with the file usersRoute.js :
const express = require("express");
const router = express.Router();
const User = require("../models/userModel");
router.post("/login", async(req, res) => {
const { username, password } = req.body;
try {
const user = await User.findOne({ username, password });
if (user) {
res.send(user);
} else {
return res.status(400).json(error);
}
} catch (error) {
return res.status(400).json(error);
}
});
router.post("/register", async (req, res) => {
try {
const newuser = new User(req.body);
await newuser.save();
res.send("User registered successfully");
} catch (error) {
return res.status(400).json(error);
}
});
module.exports = router;
I'm also using this method to make a get request to another endpoint in a carsRoute.js file which looks like this (the get request works) :
const express = require("express");
const router = express.Router();
const Car = require("../models/carModel");
router.get("/getallcars", async(req,res) => {
try {
const cars = await Car.find()
res.send(cars)
} catch (error) {
return res.status(400).json(error);
}
})
module.exports = router;
Finally, I export them into server.js which looks like this :
const express = require('express');
const app = express();
const port = process.env.port || 5000;
const dbConnect = require('./db');
app.use(express.json())
app.use('/api/cars/' , require('./routes/carsRoute'))
app.use('/api/users/', require('./routes/usersRoute'))
app.get('/', (req,res) => res.send('Hello World') )
app.listen(port, () => console.log(`Node Js Server Started on port ${port}`))
I do not think i missed any "/" or have any additional ones.