Facebook first acknowledged the problems in a tweet Wednesday at 1:49 p.m. ET, then said in a follow-up message that it was able to confirm the outages were not caused by distributed denial-of-service attack, in which networks are overloaded with bogus traffic created to disrupt service.
A spokesman for the social network said the company was cooperating with investigators in multiple federal probes, without addressing the grand jury inquiry specifically.
The company also said it was considering whether to refund advertisers for lost exposure due to the problems, which internet outage trackers showed affected users in Europe, Japan, North and South America.
Facebook's stock fell almost 3% in early morning trading on Thursday as Wall Street reacted to the outage. In a tweet about 24 hours after the problems began, Facebook apologized and thanked people for their patience.
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.
"Yesterday, a server configuration issue made it hard for people to access our apps and services. We're working to resolve the issue as soon as possible", Facebook tweeted around 2 p.m. ET.
Frank Lampard urges Callum Hudson-Odoi to stay at Chelsea
It's a mad one because a young English player at Chelsea at that age then you really want him to sign that long-term contract. Chelsea have invested heavily in the academy and I'm sure they are going to want to see the fruits of that.
Outcry over Trump's cuts to Medicare hospital payments
Trump's proposals met with immediate criticism from the host of candidates for the Democratic presidential nomination. Nevertheless, the budget also includes an additional $8.6 billion to construct walls right along the Mexican border.
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What had been a 26th player for certain day-night doubleheaders through August 31 will become a 27th player in those situations. From September 1st through the end of the championship season, all Clubs must carry 28 players on the active roster.