Facebook apologized late Monday for a massive outage that knocked out service to the social media giant's platforms for users around the world, and said the disruption was due to a "faulty configuration change."
The company said no user data had been compromised in the blackout, which left Facebook, Instagram and WhatsApp down for more than six hours.
All three platforms, owned and operated by Facebook Inc., based in Menlo Park, California, went out of service at 11:39 a.m. ET. By around 6 p.m. ET, users of all three platforms reported that some service had been restored, but full functionality remained elusive well into Monday evening.
"Our engineering teams have learned that configuration changes on the backbone routers that coordinate network traffic between our data centers caused issues that interrupted this communication," the company said in a statement late Monday.
"This disruption to network traffic had a cascading effect on the way our data centers communicate, bringing our services to a halt."
CEO Mark Zuckerberg, in a Facebook post at 6:54 p.m. ET, also apologized. "Sorry for the disruption today — I know how much you rely on our services to stay connected with the people you care about."
A Facebook employee said it appeared to be a problem with the Domain Name System, the "phone book" of the internet, which computers use to look up individual websites.
"I wish I knew. No internal tooling, DNS seems totally borked. Everyone is just sort of standing around," the source said. "No reason at this point to suspect anything malicious, but the outage is affecting pretty much everything. Can't even access third-party tools."
And a WhatsApp employee said no internal services at company headquarters worked except for email and calendars.
Even conference rooms were inaccessible during the outage, the employee said, because they’re digitally locked and unlocked through an internet-connected tablet.
The outage comes a day after Facebook faced allegations from a whistleblower that it had turned a blind eye to disinformation that led to the deadly Jan. 6 riot at the U.S. Capitol.
“Facebook, over and over again, has shown it chooses profit over safety,” former Facebook data scientist Frances Haugen said on CBS' "60 Minutes" in an episode that aired Sunday night.
She is scheduled to testify before a Senate subcommittee Tuesday.
A Facebook spokeswoman, responding to the "60 Minutes" report, said the company has made "significant improvements to tackle the spread of misinformation and harmful content."
Including the Facebook CTO, Monday’s outage drove many social media users to Twitter. The platform responded to the influx by rolling out the digital welcome mat, saying simply, "hello literally everyone."