For security reasons, we need to make sure you are interacting with only the Duolingo English Test application while you are taking the test. If you click on or open anything other than the test application, your test will be cancelled and you will need to retake it from the beginning. This will also use up one of the attempts on your test credit.
To prevent this from happening again, make sure to close all other programs that are running on your computer before taking the test.