Hi, I'm using cloudinary for hosting videos, and i want to create temporary links as a way to protect the videos that are hosted. I sign the upload on the front end, using cloudinary's upload widget and a route. This returns a signed URL that works fine, but i want to add a time restriction and deliver the video to the user through that link, but when i try to sign the url with the restriction on the backend, an error shows up saying that the resourse wasn't found, when I try to access the new link. I'm using next-cloudinary.

this is my backend controller

require("dotenv").config();
const cloudinary = require("../../utils/cloudinary");
const { CLOUDINARY_API_SECRET } = process.env;
const Videos = require("../../models/Videos");

async function getVideoById(req, res, next) {
  try {
    const { id } = req.params;
    const video = await Videos.findById(id);
    if (!video) res.status(404).json({ message: "Video no encontrado" });

    // Genera una firma con una validez de 60 segundos
    const currentTimeInUTC = Math.round(Date.now() / 1000);
    const expiresAt = currentTimeInUTC + 60;

    const signature = cloudinary.utils.api_sign_request(
      `${expiresAt}`,
      CLOUDINARY_API_SECRET
    );

    console.log('signature' , signature);
    // Usa private_download_url para generar la URL privada
    const secureVideo = cloudinary.utils.private_download_url(video.id, "mp4", {
      expires_at: expiresAt,
      signature: signature
    });

    return res.status(200).json({ url: secureVideo });
  } catch (error) {
    next({ message: error.message, statusCode: 404 });
  }
}

module.exports = getVideoById;