The Google Classroom integration is enabled on customer sites by default. This integration enables Google Classroom sharing and grade pass-back. Site Admins have the ability to disable Google Classroom integration from their customer Site.

If you would like to disable re-enable this option, please follow the steps below.

Click on the drop-down arrow next to your name.
Select "Admin."
Click on "Settings."
Click on the pink "Edit" button on the right.
Under "Options > Student functionality," check if the toggle is turned to "On." Google Classroom integration does not work if Student functionality is turned off.
Under "Options > Google Classroom," click on the toggle and shift it to "Off" to turn it off, or to "On" to turn it on again.
Click on the pink "Save changes" button at the top of the page.

Enabling and Disabling Google Classroom Integration