Group Gator's services scopes have changed since you originally authorized them. As a result, you should be requested to re-authorize the application with it's new required permissions.
Please navigate to the following page and remove Group Gator's Permission by clicking on the Group Gator app and clicking the "Remove" button.
Then navigate here and re-authorize the Group Gator Service using your Super Admin Account.
If you see the Warning that "This app is not verified" - Our Labs team is working with Google to get the service verified. Until then, click the "Advanced" link and then click "Go to Group Gator (unsafe)" and review and accept the permissions Group Gator will need.
Once you've done this, the Delegation Service should be available once again.