The outages on Facebook, Instagram, and WhatsApp yesterday reportedly caused Facebook head Mark Zuckerberg to lose over $6 billion within a few hours.

The outages reportedly came after a former employee Frances Haugen called out the company as a whistleblower. Now, Zuckerberg addressed users of the platforms via Twitter and said, “Facebook, Instagram, WhatsApp, and Messenger are coming back online now. Sorry for the disruption today—I know how much you rely on our services to stay connected with the people you care about.”

The VP of Engineering and infrastructure for Facebook—Santosh Janardhan, spoke on the outage and said:

“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. This disruption to network traffic had a cascading effect on the way our data centers communicate, bringing our services to a halt.”