As of 8:43 AM EST, Instructure identified increased errors which affected features such as SpeedGrader and DocViewer, which allows users to view linked documents in-line in Canvas. Currently, this has resulted in users are receiving 502/503 errors or “Service is currently unavailable. Try again later.” messages when accessing content in Docviewer. Canvas Engineering team is currently implementing a fix to resolve these issues. You can check the status of Canvas on Canvas status page where we will post updates as they are available.