The best way to fix any issues with the Google Single Sign-On or Google Classroom is to remove Convoer Online's access to your google account and relink the account.
First, go to https://myaccount.google.com/
Select the Security section.
Scoll down the section and find Third-party apps with account access. Select the Manage third-party access link. Here is the direct link: https://myaccount.google.com/permissions
Find any Conover Online entries and click on it.
Select the REMOVE ACCESS button.
You will be prompted with a question asking if you want to remove access. Select OK.
You can now go back to Conover Online and relink your Google account.