Facebook-owned Instagram, WhatsApp, and Messenger were experiencing global intermittent outages on Monday. DNS issues are being identified as the cause of the extensive outages. 

The problem began around 11:45 am EST. , according to DownDetector, and were hitting users globally. Shortly after noon, the Facebook website was returning the message that read, “This site can’t be reached.”

Around 12:30 pm EST, outages began to subside. But tens of thousands of users all over the world were still reporting problems. 

When Facebook went down, Twitter got busy.

DNS issues caused outages

Dylan Byers of Puck News tweeted a company-wide internal memo was sent to Facebook employees. The outages are allegedly caused by  “a DNS issue that is impacting both internal and external access to our tools and apps,” according to Byers.

The Domain Name System (DNS) connects each domain name to the right IP address enabling users to access popular websites. In July, a sweeping outage of a major DNS operator hit several major platforms including Google, Amazon, Fidelity, Costco, Delta Air Lines, British Airways, and Capital One. 

Facebook spokesman Andy Stone, acknowledged the problems on Twitter. He tweeted out, “We’re aware that some people are having trouble accessing our apps and products. We’re working to get things back to normal as quickly as possible, and we apologize for any inconvenience.”

The reported DNS failure was mainly impacting Facebook-owned platforms. But cell phone carriers including T-Mobile, Verizon, and AT&T also reported problems. DownDetector says the outages happened around the same time but were not as widespread.

“Instagram and friends are having a little bit of a hard time right now, and you may be having issues using them. Bear with us, we’re on it!” Instagram said in a tweet.

“We’re working to get things back to normal and will send an update here as soon as possible. Thanks for your patience!” WhatsApp added.

Facebook also owns Oculus, the virtual reality gaming platform, which was experiencing the same system outages.

“We’re aware that some people are having trouble accessing our apps and products. We’re working to get things back to normal as quickly as possible, and we apologize for any inconvenience,” was tweeted out.

Shares of Facebook were trading down more than 5 percent. 

DNS issues are not the only thing that can bring down the tech giants. Major websites can also go offline if Content Delivery Networks (CDNs)crash. This happened in June, due to a Fastly crash.