404. That’s an error.

The requested URL /_layouts/15/appredirect.aspx?client_id=i%3A0i%2Et%7Cms%2Esp%2Eint%7C31463909%2Deb54%2D4863%2Db851%2De5ed3c9bee9a%40a356cc72%2D5b64%2D46ad%2D8e9f%2D9da7dd67fb01&redirect_uri=%7EappWebUrl%2FPages%2FDefault%2Easpx%3F%7BStandardTokens%7D was not found on this server. That’s all we know.