Facebook and photo-sharing app Instagram were down for 40 minutes Tuesday.
The two popular social networking sites were back online after users worldwide experienced difficulty connecting to them, both on the Web and via mobile apps.
While the hacker group Lizard Squad claimed responsibility of taking the site down, Facebook said it believed its own engineers caused the problem after introducing a change that affected its configuration systems.
The shutdown first occurred at around 1:10am ET, as users trying to login were denied access, and read the message: "Sorry, something went wrong. We're working on it and we'll get it fixed as soon as we can." However, Facebook-owned mobile messaging service WhatsApp was not affected.
The last instance of Facebook going down was back in September, when the social network went down twice. The most recent outage lasted about 15 minutes.
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