If Google Classroom, or any Google Product, does not load for you, try these steps.
Step 1: Make sure you are logged into your Noble Knights Account. This needs to be the account used when initially logging into the Chromebook.
Step 2: From any tab, click on the three dots in the upper right-hand corner. Select settings. Select Advanced. Select Restore settings to their original defaults.
Step 3: Go back to the three dots and click on History. In the menu that pops up to the left, click history at the top of the list. Select Clear Browsing History. Select All time, Cookies and other site data, and Cached images and files. Then click Clear data.
Step 4: Restart your Chromebook.