The most common issue is that Google is trying to give you access from a personal Gmail account that you're logged into in the background, but the shared drive is only visible to rfschools users. This can happen even though you just logged into this website with your rfschools account.
### Chromebook users: Remove your personal Gmail account from this instance of Chrome (you can still access your personal Gmail by signing out of your Chromebook, then clicking 'Add Person,' and signing back in)