Easily verify if your tracking code has been installed properly by following this easy step available on this page.
Make sure your account has a valid subscription (a free account has a subscription called Standard as well). To do so, go to your Account Settings.
You can see your monthly allowance here.
You user might have opt-out or has instructed their browser to ask for a DNT (Do Not Track). You can find more informations on our ressources pages.