Facebook’s hours-long outage on Monday left its nearly 3 billions users unable to connect with each other on the service, and apparently not everyone was content to wait for the social networking giant to work out its problem.

The company behind Telegram, an instant-messaging-app rival to Facebook’s Messenger, said Tuesday that it added 70 million users while Facebook was offline Monday, in what Telegram’s founder and CEO described as a “record increase in user registration and activity” for the service.

“I am proud of how our team handled the unprecedented growth because Telegram continued to work flawlessly for the vast majority of our users,” Pavel Durov wrote on his Telegram channel, adding that the service wasn’t without its own hiccups on Monday.

“That said, some users in the Americas may have experienced slower speed than usual as millions of users from these continents rushed to sign up for Telegram at the same time,” he added. Released in 2013, Telegram has roughly 500 million monthly users.

Facebook said late Monday that the company believes a “faulty configuration” change caused a widespread outage that lasted roughly six hours.

Rival messaging app Signal also reported Monday that “millions of new people” joined its service on Monday as well.

The massive outage may’ve cost Facebook more than users; Fortune and Snopes estimate that the world’s largest social network lost at least $60 million in revenue after its apps, including Instagram and WhatsApp, went offline Monday morning.