WhatsApp users have been up in arms after the messaging service went down across the globe for 45 minutes.
The service failed about 7.30pm AEDT, showing just a buffer wheel and a "connecting" message when users tried to get online.
The UK was hit, as well as Russia, Brazil, South Africa, parts of India, Malaysia, Spain, Germany and well as some users in Australia, according to Downdetector.co.uk.
A Facebook spokeswoman in Singapore said the company was investigating the outage.
Whatsappdown was the top trending item on Twitter in India, which is its biggest market with about 200 million of its billion-plus users.
Thousands took to Twitter to express their dismay at the interruption to their social lives.
"For a moment I thought I was boring that my friends are angry at me," one user posted.
"Then I realised that WhatsApp is down.
"Thanks to Twitter."
Another wrote: "Who else came here to see if WhatsApp is down?"
But customers saw the funny side when the service resumed.
"I actually had to phone someone because of Whatsapp. Tonight we head for the streets my children," one person posted.
Another joked: "2 mins of silence for those who uninstalled and then installed WhatsApp again #WhatsAppDown."