Do you have multiple google accounts including personal or multiple district accounts? You might be getting restricted access notifications from shared items when you try to open them. The cause of this could be because you are logged in as a different account. 

If you are using the chrome browser or on a google page (gmail, docs, google.com)  an easy way to tell is in the top right hand corner of the browser select the picture icon and the account at the top is your current default account you are logged into. If you need to switch accounts simply click on one of the other accounts in the list or select add account and log in to the account you need to view documents. 

  

A quick youtube reference is below on switching to different accounts.