Flask redirect not working on heroku app

I am using flask on Heroku app. the front end is built using html and js and running in chrome. I am trying to send a redirect using the following code:

@app.route('/thanks')
def thanks():
    return "thanks"


@app.route('/upload', methods=['POST'])
def save_photos():
    for file in request.files.keys():
        createFileInS3(file, "a", request.files[file])

    return redirect("www.ynet.com", 300)

and get the following statement in chrome debug console

Redirecting...

Redirecting...

You should be redirected automatically to target URL: www.ynet.com. If not click the link.

What am i doing wrong here? how can I redirect a page to another?