Facebook said a change in the way it configured computer servers caused a widespread outage of the social-media network and its other services that stretched over two days.
“As a result of a server configuration change, many people had trouble accessing our apps and services,” Facebook said in a tweet.
“We’ve now resolved the issues and our systems are recovering.”
From about noon Wednesday, global users encountered only partially loaded pages or no content at all on Facebook’s main social network and its related services, including photo-sharing site Instagram and messaging tools Messenger and WhatsApp.
Several brand marketers tweeted that Facebook’s ad-buying system was down as well. The company said it was considering refunds for advertisers. Ad sales are the company’s central revenue source.
Instagram service resumed shortly after midnight, the app tweeted from its official Twitter account.
Shares declined 1.8 percent in New York, and have jumped 32 percent this year through Wednesday’s close.