We have noticed that students on an updated version of the ChromeOS are being logged out of their devices when a teacher attempts to allow a site.
The reason for this is an update in the new ChromeOS version that forces users to authenticate in the ChromeOS when logging out of Google. We are currently working on a fix for this problem. We recommend that until the fix is introduced schools should advise their students to not update to the latest ChromeOS version. We will inform you as soon as we have the solution in place.