Users can restrict Google Docs so that only users with @anderson.edu accounts can view the document. As a result, those trying to access the document will need to sign into their anderson.edu account to access the document. The error message can occur when you are already signed into a non-anderson.edu account (personal email and trying to access the document). Change your account to the anderson.edu email and you'll be able to access the document.
Users can sometimes see annoying popups in their web browsers. While harmless in nature; pressing the "close" button doesn't actually close them. To remove them you will need to remove them from the browser notification settings. This article is written from a Google Chrome perspective but can be applied to Firefox, Safari, Edge, etc.