I receive an error 500 using the example API script on the NextJS website (https://nextjs.org/docs/pages/building-your-application/routing/api-routes)

import type { NextApiRequest, NextApiResponse } from 'next'

type ResponseData = {
    message: string
}

export default function handler(
    req: NextApiRequest,
    res: NextApiResponse<ResponseData>
) {
    if (res) {
        res.status(200).json({ message: 'Hello from Next.js!' })
    }
}