Make folder to zip folder in vercel nodejs server

Question

Frontend - Reactjs API - nodejs

I am using Vercel for hosting nodejs

Problem I just want to make particular folder to zip folder in nodejs server, Its working fine in local but not working in Vercel

exports.download = async (req, res, next) => {
    try {

        var zip = new admz();
        let folderPath = path.join(process.cwd(), `/tmp/foldername)
        await zip.writeZipPromise(`${folderPath}.zip`); 

        return res.status(200).json({ message: "Downlading",url:`tmp/folderPath.zip` });
    }catch(error){
        console.log(error)
        return next(new AppError(error.message, 500));
    }
}

//await zip.writeZipPromise(${folderPath}.zip) - I am getting CORS issue when I am adding this line

Frontend

        let res = await downloadAPI(datas);
        let url = res.url
        let link = document.createElement('a'); 
        link.href = url;
        link.setAttribute('download', 'file.zip'); //set download attribute to link
        document.body.appendChild(link);
        link.click();

Why getting CORS issue when only creating zip folder

Access to XMLHttpRequest at 'https://XXXX/downloadAPI' from origin 'https://xxxx.vercel.app' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.