POST Route Is Giving CryptoJS Malformed Data Error

I’m learning Crypto.JS and Node.JS, and am currently struggling with a Malformed UTF-8 data error when accessing the login endpoint with Postman. I know that the login credentials are correct, but when I send the POST request to the endpoint, it throws me with that error. Is there a simple fix for this?

const router = require('express').Router();
const User = require("../models/User");
const CryptoJS = require("crypto-js");

router.post("/register", async (req, res) => {
    const newUser = new User({
        username: req.body.username,
        email: req.body.email,
        password: CryptoJS.AES.encrypt(req.body.password, process.env.SECRET_PASSPHRASE).toString()
    });

    try {
        const savedUser = await newUser.save();
        res.status(201).json(savedUser);
    } catch (err) {
        res.status(500).json(err);
    }
});

router.post("/login", async (req, res) => {
    try {
        const user = await User.findOne({ username: req.body.username })

        !user && res.status(401).json("Invalid username or password");

        const hashedPassword = CryptoJS.AES.decrypt(user.password, process.env.SECRET_PASSPHRASE);
        const originalPassword = hashedPassword.toString(CryptoJS.enc.Utf8);
        
        originalPassword !== req.body.password && res.status(401).json("Invalid username or password");

        const accessToken = jwt.sign(
        {
            id: user._id,
            isAdmin: user.isAdmin
        }, 
        process.env.ACCESS_TOKEN_SECRET,
        {expiresIn: "3d"}
        );

        const { password, ...others } = user._doc;

        res.status(200).json(others, accessToken);

    } catch(err) {
        console.log(err);
        res.status(500).json(err);
    }
});



module.exports = router;