NEW YORK — WhatsApp’s 450 million worldwide users were briefly unable to access the smartphone free-messaging service on Saturday, three days after Facebook declared it was lavishing up to $19 billion on it.

“Sorry we currently experiencing server issues. We hope to be back up and recovered shortly,” WhatsApp said in a message on Twitter that was retweeted more than 25,000 times in just a few hours and provoked ridicule because it comes so soon after Facebook’s hefty acquisition.

The service began to come back online after midnight Israel time, The Associated Press reported.

WhatsApp and Facebook didn’t responded to emails seeking comment, but the WhatsApp Status account on Twitter said service had been restored and apologized for the downtime.

Service outages are common for rapidly growing technology companies, and the WhatsApp Status account has tweeted about an outage about once a month going back through May.

During the outage, some WhatsApp users found they were unable to connect to the app, while others complained their messages were not going through.

The specialist website techcrunch.com suggested the problem might have been caused by “a surge of signups and usage that has overloaded its servers” after the publicity the app garnered after Facebook’s announcement on Wednesday.

Facebook is betting huge on mobile with the eye-popping cash-and-stock deal for WhatsApp, which was only started five years ago but has quickly grown as a free alternative to text messages.

Jan Koum, one of WhatsApp’s founders, is a Jewish immigrant to the US from the USSR. His experiences growing up in the Soviet Union and arriving in the US as a penniless immigrant figure in many of the features of the app and his company.

The purchase, announced Thursday, is Facebook’s biggest acquisition and comes less than two years after the California-based Internet star raised $16 billion in the richest tech sector public stock offering.

The outage was the source of much amusement — as well as anger — on Twitter.

“I expect you are all away from your desks on the ales drinking some of that Facebook cash!” one user, “leonclarance,” replied to WhatsApp’s tweet about the blackout.

Another simply tweeted: “Turn down Facebook’s offer guys!”

AP and Times of Israel staff contributed to this report.