In order to log in or sign up on EDpuzzle you have to enable cookies and pop-ups. In this article we explain you how to do so:
Cookies are used to store information directly on your web browser and they are necessary on the log in/sign in process. To enable cookies you need to modify your browser's security settings, to do so please choose your browser from the following links: Chrome or Internet Explorer
Also, you can click on this button (located at the top-right corner) and select the option 'Always allow', as shown in the image.