If you try to download from a private Twitter account, you will get the following error message "Failed. You must be logged in to do this. Import cookies from browser.". That's because private Twitter accounts are not accessible to the general public. In order to download from the private Twitter account using WFDownloader App, you'll have to import cookies from your browser into the application for Twitter. After that, just follow the steps outlined above and it will now work. Please note that you must be an approved follower of the private Twitter account.