Maybe you’ve seen this error before:
The explanation is somewhat simple, even if the cause might not be: It means that there was some sort of error while loading the Azure AD authentication page. 99% of the time it’s going to be a network error – the page being displayed is effectively a web page that is fetched from the cloud and rendered on screen (the blue area). If something gets in the way of that, i.e. a firewall or other flaky connection, you’ll see this error.
But what is actually being accessed to narrow it down a little more? If you check the event log on the device, more specifically the Microsoft-Windows-Shell-Core/Operational log (just Shell-Core -> Operational in the Event Viewer UI), you will see the URLs being access and whether or not they were successful. If you did a network trace (see my previous blog on using Fiddler for that), you would see these two URLs:
- login.microsoftonline.com. This site returns the main AAD sign-in page itself.
So the next time you see this error, you know where to look.