Testing "sample web App" . Fail to join the meeting

Hi, I’m new to Zoom. what I’m trying to do is to integrate zoom meeting into my ReactJS app.
first of all, I tried to use the zoom sample web app to check how it works.
so I cloned this project from GitHub - zoom/sample-app-web: Zoom Meeting SDK for Web Sample App
following the readme instruction
I created a new app in the marketplace.zoom to get needed credentials API__key API_secrect also I used this function to create a new signature


function generateSignature(apiKey, apiSecret, meetingNumber, role) {
  // Prevent time sync issue between client signature generation and Zoom
  const timestamp = new Date().getTime() - 30000
  const msg = Buffer.from(apiKey + meetingNumber + timestamp + role).toString('base64')
  const hash = crypto.createHmac('sha256', apiSecret).update(msg).digest('base64')
  const signature = Buffer.from(apiKey, meetingNumber, timestamp, role, hash).toString('base64')
  return signature
}

but when I tried to join a meeting
I got this error

{
    "type": "JOIN_MEETING_FAILED",
    "reason": "Fail to join the meeting.",
    "errorCode": 200
}

Can you please help me out?