Integration of pre-recorded video with RTC

I have deployed the code and MP4 file on server end as you described but still I am getting black video. @mihailj Below is my code

const connect = function (fileName, SESSION_ID) {
  try {
    var postData = JSON.stringify({
      type: "IPCAM",
      rtspUri: "file:///opt/openvidu/recordings/" + fileName + ".mp4",
      adaptativeBitrate: true,
      onlyPlayWithSubscribers: true,
      networkCache: 2000,
      data: "IP-CAM",
    });

    var options = {
      hostname: HOST_NAME,
      port: 4443,
      path: "/openvidu/api/sessions/" + SESSION_ID + "/connection",
      method: "POST",
      headers: {
        Authorization: "Basic " + btoa("OPENVIDUAPP:" + SECRET),
        "Content-Type": "application/json",
        "Content-Length": postData.length,
      },
    };

    var req = https.request(options, (res) => {
      console.log("statusCode:", res.statusCode);
      console.log("headers:", res.headers);

      res.on("data", (d) => {
        console.log("loaded");
      });
    });

    req.on("error", (e) => {
      console.error(e);
    });

    req.write(postData);
    req.end();
  } catch (e) {
    console.log(e.message);
  }
};