WhatsApp has confirmed it is running as usual after more than 40,000 people in the UK reported issues with the messaging service.
As of 9.59pm, a total of 41,095 outages had been recorded by website monitoring service, Downdetector.
However, by 10.08pm the number of issues reported dropped to just over 36,000.
The site showed issues with the app began at around 9pm.
Most of the problems were reported in London, Manchester and Birmingham.
However, outages may have been experienced worldwide as the service tweeted from California that it was aware of "some issues" and it was "working to get things running smoothly again".
"We'll keep you updated and in the meantime, thanks for your patience," it added.
Within an hour and a half of the problem being reported, the number of users experiencing a technical fault fell to 2,707.
By 10.45pm, WhatsApp confirmed the issue had been resolved, tweeting: "And we're back. Happy chatting."
Facebook also seemed to be suffering smaller problems, with more than 200 users reporting an issue with the social network around the same time.
Both are owned by Mark Zuckerberg's Meta Platforms.