After a brief suspension of the WhatsApp messaging service in Brazil, a court there overturned an order from a lower court which had placed a ban on the Facebook-owned app.
A judge in Brazil put the ban on the service Wednesday night, after the company failed to comply with an order to provide information for a criminal investigation. The ban was originally scheduled to last 48 hours.
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Facebook bought WhatsApp for $19 billion last year.
The social network's co-founder and CEO, Mark Zuckerberg, posted a message to Brazilians on his Facebook page. "I am stunned that our efforts to protect people's data would result in such an extreme decision by a single judge to punish every person in Brazil who uses WhatsApp."
Zuckerberg said the app had 100 million users in Brazil before the ban.
Telegram Messenger, a rival, said it gained 1.5 million new users when WhatsApp went dark, according to the company's Twitter feed @telegram.
