Zalo mobile users in Vietnam report outage

"At first, I thought there was something wrong with the Internet, but I tried Wi-Fi, 4G and even restarting the phone to no avail," said Ngoc Anh, who lives in Hanoi's Cau Giay District.

Anh said she rarely uses Zalo, but a friend sent her a message on the app on Friday, so she had to open it up.

"When I opened the chat, the application could not download new messages. The message I sent was in the 'sending' state for an hour," she said.

Several users reported the same thing, mostly starting around 11 a.m. When people tried to send messages, finding friends or accessing the app, Zalo would instead show notifications like "Connecting" or "No connection." Some said their phones still show new message notifications, but when they tried to open them, there were no new messages.

Huy Hoang, who lives in Ho Chi Minh City, said he used Zalo to order lunches as he did not save the shop's phone numbers in his contact list, but it's past noon and he still could not get in touch with the shop.

The issue mostly happened to Zalo users on their mobile phones; those using Zalo on their PCs could still send their messages normally.

"However, I tried to send many messages and no one replied. Probably because all my partners use Zalo on the phone," said Tuan Hung from Hanoi.

By 2 p.m., some people said they could send messages to others, but the connection was fickle and not entirely stable.

Zalo has yet to make any announcement or comments regarding the incident.

In October last year, several Zalo users also could not send messages over web browsers.