Thousands of Snapchat users are unable to send pictures or refresh their feeds after the app stopped working across the globe.
People said they were seeing a "could not refresh" error message.
They were also unable to send pictures and see their feed.
Huge numbers of users logged onto Twitter to complain.
Downdetector, which monitors online outages, showed that there had been thousands of reports of the app being down from around 5.30pm.
Users in the UK, Europe and the east coast of the United States are the worst affected, according to the site's outage map.
The outage prompted a flurry of tweets from concerned users.
Snapchat replied to users saying: "Hi there! Thanks for letting us know, we’re looking into this!"
They later added: "We're aware some Snapchatters are having trouble using the app. Hang tight - we are looking into it."
