Popular messaging app ‘WhatsApp’ is down, with users forced to switch to one of the many other forms of communication still in operation.

People can’t send or receive messages using the Facebook-owned app, apparently because of a server problem.

The app doesn’t initially look broken, with chats and contacts able to load. But once a user is into a chat, the app just shows a “connecting” message that never resolves itself, and so new messages can’t be sent or received.

For now, the service’s 1.2 billion users will have to resort to Twitter, Facebook, Instagram, Snapchat or good old fashioned text message.