- Facebook experienced worldwide outages for its apps and services for nearly a day, starting around noon Eastern Wednesday.
- On Thursday, Facebook blamed a "server configuration change" for the outages.
- Facebook said services were returning to normal Thursday.
Facebook users around the world reported issues logging into and posting on the site as well as on Instagram and WhatsApp thoughout the day on Wednesday. The outages lasted about a full day, and was Facebook's longest downtime ever.
In a statement Thursday, the company blamed a "server configuration change that triggered a cascading series of issues" for the outages. The company said its services were coming back online.
"Yesterday, we made a server configuration change that triggered a cascading series of issues," said a Facebook spokesperson. "As a result, many people had difficulty accessing our apps and services. We have resolved the issues, and our systems have been recovering over the last few hours. We are very sorry for the inconvenience and we appreciate everyone's patience."
Facebook previously acknowledged the outage in a tweet Wednesday, saying, "We're aware that some people are currently having trouble accessing the Facebook family of apps. We're working to resolve the issue as soon as possible."
It later confirmed the problem was not the result of a DDoS attack, which refers to a Distributed Denial-of-Service attack in which a hacker overwhelms a site by flooding it with fake traffic.
Facebook shares were relatively unchanged Wednesday afternoon but slid about 1.8 percent Thursday morning.
Reports of problems with Facebook peaked at over 12,000 worldwide late Wednesday according to Downdetector, a website where users can report problems on apps and websites. Downdetector listed over 300 reports Thursday morning, and many people reported their access had been restored, but Facebook has not yet confirmed the issues were resolved.
Users reported a variety of problems, from being unable to load the site at all to not being able to post comments. Facebook users posted screenshots on Twitter showing error messages when they tried to load the app. When loading the site, some users' got a message on the screen saying "Account Temporarily Unavailable."
At a Facebook event at the South by Southwest conference in Austin, Texas Wednesday, the company's head of video products cracked a joke when he ran into technical issues.
"Today is the technical difficulties day for Facebook, I guess," cracked Paresh Rajwat, in a reference to the company's worldwide service outage when his presentation's video failed to include audio. Rajwat was announcing new features for Facebook's Watch video service.
Technical issues with Facebook have historically posed serious problems for advertisers who use the platform and even other websites.
Facebook previously experienced an outage of its tool for advertisers in November at a time when marketers were trying to place ads for Black Friday and Cyber Monday.
In 2013, Facebook experienced a glitch which took several websites down with it thanks to the prevalence of its login feature across the internet. When users tried to log into a website with their Facebook profile, they were directed to a Facebook error page, Business Insider reported at the time. The glitch, which only lasted a few minutes, affected websites including The New York Times and CNN, Business Insider reported.
— CNBC's Salvador Rodriguez contributed to this report.