Facebook and its sister properties Instagram and WhatsApp are suffering from ongoing, global outages. We don’t yet know why this happened, but the how is clear: Earlier this morning, something inside Facebook caused the company to revoke key digital records that tell computers and other Internet-enabled devices how to find these destinations online.

Kentik’s view of the Facebook, Instagram and WhatsApp outage.

Doug Madory is director of internet analysis at Kentik, a San Francisco-based network monitoring company. Madory said at approximately 11:39 a.m. ET today (15:39 UTC), someone at Facebook caused an update to be made to the company’s Border Gateway Protocol (BGP) records. BGP is a mechanism by which Internet service providers of the world share information about which providers are responsible for routing Internet traffic to which specific groups of Internet addresses.

In simpler terms, sometime this morning Facebook took away the map telling the world’s computers how to find its various online properties. As a result, when one types Facebook.com into a web browser, the browser has no idea where to find Facebook.com, and so returns an error page.

In addition to stranding billions of users, the Facebook outage also has stranded its employees from communicating with one another using their internal Facebook tools. That’s because Facebook’s email and tools are all managed in house and via the same domains that are now stranded.

“Not only are Facebook’s services and apps down for the public, its internal tools and communications platforms, including Workplace, are out as well,” New York Times tech reporter Ryan Mac tweeted. “No one can do any work. Several people I’ve talked to said this is the equivalent of a ‘snow day’ at the company.”

The outages come just hours after CBS’s 60 Minutes aired a much-anticipated interview with Frances Haugen, the Facebook whistleblower who recently leaked a number of internal Facebook investigations showing the company knew its products were causing mass harm, and that it prioritized profits over taking bolder steps to curtail abuse on its platform — including disinformation and hate speech.

We don’t know how or why the outages persist at Facebook and its other properties, but the changes had to have come from inside the company, as Facebook manages those records internally. Whether the changes were made maliciously or by accident is anyone’s guess at this point.

Madory said it could be that someone at Facebook just screwed up.

“In the past year or so, we’ve seen a lot of these big outages where they had some sort of update to their global network configuration that went awry,” Madory said. “We obviously can’t rule out someone hacking them, but they also could have done this to themselves.”

Update, 4:37 p.m. ET: Sheera Frenkel with The New York Times tweeted that Facebook employees told her they were having trouble accessing Facebook buildings because their employee badges no longer worked. That could be one reason this outage has persisted so long: Facebook engineers may be having trouble physically accessing the computer servers needed to upload new BGP records to the global Internet.

Update, 6:16 p.m. ET: A trusted source who spoke with a person on the recovery effort at Facebook was told the outage was caused by a routine BGP update gone wrong. The source explained that the errant update blocked Facebook employees — the majority of whom are working remotely — from reverting the changes. Meanwhile, those with physical access to Facebook’s buildings couldn’t access Facebook’s internal tools because those were all tied to the company’s stranded domains.

Update, 7:46 p.m. ET: Facebook says its domains are slowly coming back online for most users. In a tweet, the company thanked users for their patience, but it still hasn’t offered any explanation for the outage.

Update, 8:05 p.m. ET: This fascinating thread on Hacker News delves into some of the not-so-obvious side effects of today’s outages: Many organizations saw network disruptions and slowness thanks to billions of devices constantly asking for the current coordinates of Facebook.com, Instagram.com and WhatsApp.com. Bill Woodcock, executive director of the Packet Clearing House, said his organization saw a 40 percent increase globally in wayward DNS traffic throughout the outage.

Update, 8:32 p.m. ET: Cloudflare has published a detailed and somewhat technical writeup on the BGP changes that caused today’s outage. Still no word from Facebook on what happened.

Update, 11:32 p.m. ET: Facebook published a blog post saying the outage was the result of a faulty configuration change:

“Our engineering teams have learned that configuration changes on the backbone routers that coordinate network traffic between our data centers caused issues that interrupted this communication,” Facebook’s Santosh Janardhan wrote. “This disruption to network traffic had a cascading effect on the way our data centers communicate, bringing our services to a halt.”

“We want to make clear at this time we believe the root cause of this outage was a faulty configuration change,” Janardhan continued. “We also have no evidence that user data was compromised as a result of this downtime.”

Several different domain registration companies today listed the domain Facebook.com as up for sale. This happened thanks to automated systems that look for registered domains which appear to be expired, abandoned or recently vacated. There was never any reason to believe Facebook.com would actually be sold as a result, but it’s fun to consider how many billions of dollars it could fetch on the open market.

This is a developing story and will likely be updated throughout the day.