CGDisplayCreateImage not able to take screenshots(only returns wallpaper and task bar)

Question

I want to take screenshot programmatically in Swift, macOS I followed the below link Programmatically Screenshot | Swift 3, macOS Code is here

    var displayCount: UInt32 = 0;
    var result = CGGetActiveDisplayList(0, nil, &displayCount)
    if (result != CGError.success) {
        print("error: \(result)")
        return
    }
    let allocated = Int(displayCount)
    let activeDisplays = UnsafeMutablePointer<CGDirectDisplayID>.allocate(capacity: allocated)
    result = CGGetActiveDisplayList(displayCount, activeDisplays, &displayCount)
    
    if (result != CGError.success) {
        print("error: \(result)")
        return
    }
       
    for i in 1...displayCount {
        let unixTimestamp = CreateTimeStamp()
        let fileUrl = URL(fileURLWithPath: folderName + "\(unixTimestamp)" + "_" + "\(i)" + ".jpg", isDirectory: true)
        let screenShot:CGImage = CGDisplayCreateImage(activeDisplays[Int(i-1)])!
        let bitmapRep = NSBitmapImageRep(cgImage: screenShot)
        let jpegData = bitmapRep.representation(using: NSBitmapImageRep.FileType.jpeg, properties: [:])!
        
        let fileManager = FileManager.default
        
       
        do {

            let documentDirectory = try fileManager.url(for: .documentDirectory, in: .userDomainMask, appropriateFor:nil, create:false)
            let fileURL = documentDirectory.appendingPathComponent("\(unixTimestamp)" + "_" + "\(i)" + ".jpg")
           
                try jpegData.write(to: fileURL)
                
           
        } catch {
           print(error)
        }

}

But I am getting this output. enter image description here