Resolved - We experienced an outage, and the application could not be accessed for a total of four hours due to a database error. Most of the pages were not affected by this incident, as they were cached on our servers, but some of them might have returned 404 status code for the time the app was down.

We apologize and want to assure you that we will work even harder to ensure that roadblocks like these stop occurring in the future. Also, we are working on a permanent fix that will prevent such errors from appearing in our application in the future.
Sep 13, 10:30 UTC