Facebook is blaming a 'faulty configuration change' for its biggest ever outage.
The social media site, along with WhatsApp and Instagram were down for nearly six hours last night.
It has apologised to the company's 3,500,000,000 users who depend on their platforms.
Technology Correspondent, Jess Kelly, says there's little detail about what exactly happened.
"We still don't know why this has happened.
"It seems that something within Facebook caused key digital records that tell computers how to find apps and websites was revoked.
"It's still not clear if this was intentional, if it was human error or if it was the work of a bad actor."
