Test is showing a blank page or grey screen
Most likely, this is because of an issue with your login. You are logged in with a Google account that doesn't allow you access to the test. Logout of all your Google accounts by clicking on https://accounts.google.com/Logout
For more information, read these instructions for a Timed Test, and these instructions for a Proctored Test. Scroll down the section that says Google Accounts.
Updated on: 11/21/2022