MIT App Inventor not connecting to IOS Devices

My students have been using MIT App Inventor all year with IOS devices. Today they are unable to connect at all. What has changed and when might it be fixed? Thanks

Some schools have been reporting issues with the popup functionality in App Inventor for iOS 2.64. When this has been a problem, it is usually because there is some school software blocking the popup.

If the popup opens but you see an error message, then it's most likely that the school has blocked communication between the computer running App Inventor and the device running the companion on TCP port 8001. This port must be open for the App Inventor software to talk to the companion.

If the popup opens but the progress bar gets stuck as 10%, this is usually caused by some browser extension interfering with the popup. Using a guest account in Chrome seems to work around the issue but we're not sure why.