A "cascading" infrastructure glitch forced popular social network Twitter offline last night, for several hours from around 5pm GMT.
Twitter struggled to restore service, announcing success about an hour after the outage began, only to have the network go down again shortly after that.
Explaining the down time in a blog post, Twitter engineer Mazen Rawashdeh said that the outage was down to "a cascading bug in one of our infrastructure components".
"This wasn’t due to a hack or our new office or Euro 2012 or GIF avatars, as some have speculated today," Rawashdeh wrote. "A ‘cascading bug’ is a bug with an effect that isn’t confined to a particular software element, but rather its effect “cascades” into other elements as well.
"One of the characteristics of such a bug is that it can have a significant impact on all users, worldwide, which was the case today."
To get rid of the bug, Twitter was rolled back to a previous, stable version.
Twitter’s underlying IT architecture is constantly evolving. In a blog post at the end of May, the engineering team explained some of the changes to the service.
At the end of the post, engineering manager said Dan Webb said that Twitter would soon start overhauling the server side of the application.