Messaging app WhatsApp was starting to come back online at 0900 GMT and the company said the issue has been fixed after users across the world reported problems earlier on Tuesday.
At around 0750 GMT, outage reporting site Downdetector had shown over 68,000 users had reported problems with the app in the United Kingdom. Problems were reported by 19,000 people in Singapore and 15,000 people in South Africa, as well.
"We know people had trouble sending messages on WhatsApp today. We have fixed the issue and apologise for any inconvenience," a spokesperson for WhatsApp parent company Meta Platforms said.