On Monday, Facebook faced two crises: potentially billions of users were impacted when its major social network went offline for seven hours, and the firm was fighting a whistleblower’s damaging disclosures.

Many long-held concerns and criticisms of the platform appear to have been validated by Facebook’s own research, which ex-worker Frances Haugen turned over to authorities and the Wall Street Journal.

However, as US senators prepared for her highly anticipated Tuesday testimony on the papers, Facebook fell offline, affecting users across all of its platforms, including Instagram and WhatsApp.

“Billions of users have been impacted by the services being entirely offline today,” tracker Downdetector wrote on its website.

Facebook apologized in a tweet sent later Monday at Silicon Valley time, just as the apps began to re-launch.

“We’ve been working hard to restore access to our applications and services and are pleased to inform you that they are currently available,” the business wrote.

Late Monday, Facebook blamed the outage on adjustments it made to routers that coordinate network traffic between its data centers.

“This disruption to network traffic had a cascading effect on the way our data centers communicate, bringing our services to a halt,” Facebook vice president of infrastructure Santosh Janardhan said in a post.

According to cyber security expert Brian Krebs, Facebook removed “the map directing the world’s computers how to reach its many web domains.”

In addition to the inconvenience caused to people, businesses, and others who rely on Facebook’s products, Facebook CEO Mark Zuckerberg suffered a financial setback.

According to Fortune’s billionaire monitoring website, Zuckerberg’s personal fortune fell by about $6 billion from the previous day to just under $117 billion late Monday.

According to specialist business SensorTower, the messaging service Telegram rose from the 56th to the fifth most downloaded free app in the United States.

Signal, an encrypted messaging service, announced that “millions” of new users have joined, and that it was “Signal and ready to mingle.”

It was hardly the first Twitter user to make light of the outage, however, others expressed concern about being cut off from relationships, sources of money, or business tools.

Some, though, were philosophical, such as Cindy Bennett, a New York City baker, who told AFP: “I think the world would definitely be a better place if everybody didn’t know what everybody else was doing every second of every minute of every day.”

Facebook has fought back hard against the outcry over its tactics and impact, but this is only the latest crisis to strike the company.

For years, US legislators have promised to regulate Facebook and other social media behemoths in response to complaints that the platforms violate privacy, serve as a platform for hazardous misinformation, and harm the well-being of young people.

After years of criticism directed at social media, and in the absence of big legislative changes, some experts were pessimistic that change would occur.

“There will be a lot of smoke and a lot of anger, but not a lot of action,” said Mark Hass, an Arizona State University professor.

“It’s going to have to come down to the platforms, feeling pressure from their users, feeling pressure from their workers,” he added, pointing out that authorities will be unable to adequately police content.

Haugen, a 37-year-old data scientist from Iowa, has worked for firms like as Google and Pinterest, but she told CBS’s “60 Minutes” that Facebook was “significantly worse” than anything she had ever seen.

Nick Clegg, Facebook’s vice president of policy and global affairs, fiercely denied that its platforms are “poison” for minors, only days after a tense, hours-long congressional session in which US lawmakers grilled the firm on its influence on the mental health of young users.