EAB, the vendor who supports the Grades First application has reported an issue on their end. It has been fixed but it may take a few hours for DNS entries to be repopulated. EAB's email is provided below.
From: EAB Technology Notice
Date: April 20, 2017 at 11:15:47 AM EDT
To: EAB Technology Notice
Subject: RE: EAB Platform Performance
We experienced a brief outage with our DNS server which caused the intermittent access to your EAB Platform. The issue has been solved but you may experience some connection issues for 1-3 hours as the DNS settings resolve.
Again, we apologize for the inconvenience and appreciate your patience.