WhatsApp, the rapidly expanding mobile messaging app, suffered an outage for more than three hours on Saturday, frustrating users just days after its acquisition by Facebook for $19 billion.
"WhatsApp service has been restored. We are so sorry for the downtime...," WhatsApp tweeted to its more than 1 million Twitter followers on Saturday around 5:48 p.m. EST (2248 GMT).
Read: IIT-Delhi graduate head of 'all things business at WhatsApp'
Earlier, the service had said it was "experiencing server issues" without providing further details. Facebook referred questions on the outage to WhatsApp representatives, who did not immediately respond.
Read: WhatsApp founders mint billions from FB
Five-year-old WhatsApp currently has about 450 million users globally and has been adding a million users daily.
On Saturday, some of those users took to other forms of social media, including blogs and Twitter to report the outage and vent their frustration.
Read: WhatsApp brings Facebook unique value or new challenges?
WhatsApp is the leader among a wave of smartphone-based messaging apps that are now sweeping across North America, Asia and Europe, and is known to appeal to teens and others who avoid mainstream social networks.
During the outage the buzz on Twitter ranged from the conspiratorial - that Facebook had really bought WhatsApp to shut it down and funnel users to Facebook Chat - to the philosophical.
Read: Does Facebook,WhatsApp deal mean death of SMS?
"So now that #Whatsapp isn't working I've actually talked to my family, they seem like nice people," tweeted @Ali_Hilu, a self-described social media addict in Jordan.
And @Iamhollybrown of Surrey, England, scolded, "Can't believe all these people are crying about Whatsapp not working, do some exercise, do some work, learn a language."
Read: Is Facebook's $19 billion price tag for WhatsApp justified?
Read: 10 things to know about WhatsApp and its future with Facebook
Read: WhatsApp deal highlights suite of similar apps