The app was not sending or receiving messages and the independent website Down Detector detected a huge spike of outages, primarily in the UK and Europe.
The issues starting around 6pm GMT and appeared to last more than half an hour but full service has now been restored.
It was not just contained to Europe, with many users in South America, the Middle East and Asia unable to send or receive messages through the app.
The Facebook-owned app tends to be quite reliable, not often suffering major outages but as the app is used by more than one billion people around the world but any problems can affect hundreds of millions of users.
The app is the biggest messaging service globally and it is not currently known what caused the issue.