The outage eclipses YouTube's top ranking from October 17, 2018, which generated about 2.7 million problem reports on Downdetector, followed by Snapchat on November 6, 2017, with 1.8 million reports. As of Thursday morning, the only good news for Facebook is that plunging stock price appeared to have found a floor. And by 4pm, the shares dropped to 1.85 per cent.
The outage also affected Facebook Workplace and reportedly affected its ads management service.
The newspaper said the companies had access to user data that Facebook previously said was inaccessible.
However, Facebook continued sharing information with 61 hardware and software makers after it said it discontinued the practice in May 2015.
Facebook suggested there was nothing new in the New York Times report.More news: 'Game of Thrones' final season episode lengths revealed
'We've provided public testimony, answered questions and pledged that we will continue to do so, ' the spokesman said.
It is not known when the grand jury inquiry, overseen by prosecutors with the U.S. attorney's office for the Eastern District of NY, began or exactly what it is focusing on.
Facebook is facing a slew of lawsuits and regulatory inquiries over its privacy practices, including ongoing investigations by the US Federal Trade Commission, the Securities and Exchange Commission and two state agencies in NY.
In its own statement on Thursday, reported by CNBC, Facebook blamed "a server configuration change that triggered a cascading series of issues".
'Yesterday, a server configuration issue made it hard for people to access our apps and services.More news: Infiniti's killing off the QX30, and pulling out of Western Europe
The problems began yesterday (Wednesday 13 March), with almost all of Facebook's services, including mobile apps and even the Oculus Store, experiencing partial or full outages. The company said it was considering refunds for advertisers. Durov's announcement doesn't mean that three million people have abandoned Facebook, but don't underestimate the network effect if newcomers find they like Telegram and encourage their friends to join.
People used the tags to post memes about the outage, speculate about its cause and trade tips for how to survive without the company's apps.
The outages started midday on Wednesday. Users in Asia were having problems on Thursday morning.
Facebook did not say how many users were affected or why the outage was so long.
Facebook confirmed on Twitter that its suite of apps were offline for some users, stemming from server issues. "We've now resolved the issues and our systems are recovering", the company said in a tweet.More news: Cristiano Ronaldo celebrates with Simeone's 'big balls' gesture