Почему выдает ошибку - User.findOne is not a function?

const Router = require("express");
const User = require("../models/User")
const bcrypt = require("bcryptjs")
const {check, validationResult} = require("express-validator")
const router = new Router()


router.post('/registration',
    [
        check('email', "Uncorrect email").isEmail(),
        check('password', 'Password must be longer than 3 and shorter than 12').isLength({min:3, max:12})
    ],
    async (req, res) => {
    try {
        console.log(req.body)
        const errors = validationResult(req)
        if (!errors.isEmpty()) {
            return res.status(400).json({message: "Uncorrect request", errors})
        }

        const {email, password} = req.body;

        const candidate = await User.findOne({email})

        if(candidate) {
            return res.status(400).json({message: `User with email ${email} already exist`})
        }
        const hashPassword = await bcrypt.hash(password, 15)
        const user = new User({email, password: hashPassword})
        await user.save()
        return res.json({message: "User was created"})

    } catch (e) {
        console.log(e)
        res.send({message: "Server error"})
    }
})


module.exports = router