Facebook, Instagram, Messenger and WhatsApp remained down Monday afternoon after a massive outage hit the platforms.

According to CNBC, the Facebook-owned services stopped working shortly after noon Eastern Time. The websites and apps responded with service errors.

When trying to sign onto Facebook, a message said “Sorry, something went wrong. We’re working on it and we’ll get it fixed as soon as we can.”

Facebook was back up later Monday afternoon.

This marked the worst outage for Facebook since 2008. That’s when a bug knocked it offline for about a day, affecting about 80 million users. The platform now says it has 3 billion users.

The outage happened the day after the identity of Facebook whistleblower Frances Haugen was revealed on “60 Minutes“. She said documents show Facebook knows its platforms are used to spread hate, violence and misinformation, and that the company has tried to hide that evidence. She said Facebook prioritizes profits over public good.

Possible Cyberattack

Saryu Nayyar is CEO of Gurucul.

Gurucul’s Saryu Nayyar

“As more facts about Facebook and its business practices become public, its users’ anger seems to be on the rise,” she said. “If they are attackers, they respond by attacking, in this case, possibly a distributed denial of service (DDoS) attack that flooded the company’s domain name system (DNS) server.”

This isn’t the first time there has been a massive DNS attack, Nayyar said.

“DDoS attacks on Oct. 21, 2016, targeting systems operated by DNS provider Dyn took down hundreds of companies,” she said. “Many large organizations guard against the loss of their DNS by maintaining multiple DNS systems across different DNS providers. While the cause of Facebook’s problem isn’t yet clear, it would be amazing if they hadn’t already set up multiple DNS providers.”

Bill Lawrence is CISO at SecurityGate, a risk management acceleration platform.

SecurityGate’s Bill Lawrence

“Outages like this show that, for all that was learned since the DDoS attack on Dyn in October of 2016, five years later the internet remains fragile when services like DNS get interrupted for some reason,” he said. “It will be interesting to see what caused this lingering outage to several jewels in the Facebook family.”