If you have logged out of the app for any reason, you will need to login before using the app again.
Launch the app, and select “I've used the app before, and want to login again”. Enter your username (which will be either your email address or telephone number) and the password you chose when you created your account. Wait up to a minute for the login process to complete, and all of your tailored content to be downloaded. You are now ready to use the app again.