Dropbox in Europe is leaked

Yesterday, users in certain parts of Europe were reporting on the Dropbox forums saying that they couldn't log in and were receiving the spam mails from online gambling sites which was a really bad technical incident. Luckily, the Dropbox company was starting the investigation based on the report and found out that the outage was incidental and not caused by any external subject. What was the reason for the outage? Did someone trip on the cables or something? Did someone leave behind the important security feature off and not on? If the important security features are not turned on and implemented improperly, the bad chances are that there will be signs of compromising of the websites themselves holding the database of the users and their data.