If you have a passage that was shared using Fluency Tutor for Google through Google Classroom and you get the following message:
Oops :( There was an issue in trying to display this page:
Sorry, couldn’t find the file specified. Please ensure you opened the file from your own Google Drive and try again.
This means that the Classroom API needs to be enabled in the Google Admin Console
Please ask your Google administrator to follow the instructions to enable the Classroom API