The WhatsApp messaging service in Brazil is operating again after it was temporarily suspended for failing to hand over information requested in a criminal investigation.
The third suspension in two years lasted for a few hours, affecting some 100 million users.
But Supreme Court judge Ricardo Lewandowski later lifted the nationwide blockage, calling it disproportionate.
WhatsApp said they did not have access to the details requested.
“The suspension of service apparently violates the fundamental precept of freedom of expression and communication,” the Supreme Court said in its ruling.
Mr Lewandowski pointed out that the lower court judge’s decision seemed “not very reasonable and not very proportional”.
WhatsApp – owned by social media giant Facebook since February 2015 – gradually resumed normal service after the court’s ruling, correspondents say.
Earlier in the day, lower court Judge Daniela Barbosa ordered the suspension of WhatsApp, accusing its parent company Facebook of failing “to provide information that will be critical to the success of an investigation and later to bolster the criminal case”.
It is not clear which investigation she is referring to, but she said the firm had been repeatedly asked to provide messages to police investigators in the city of Caxias, north of Rio.
Taking to Facebook, WhatsApp CEO Jan Koum said it was “shocking that less than two months after Brazilian people and lawmakers loudly rejected blocks of services like WhatsApp, history is repeating itself”.
He was referring to its suspension for 72 hours in May, which forced users to turn to alternative services – a huge proportion of the internet-using population in a country with some of the world’s highest mobile phone charges.
Twitter users responded with frustration – and, in many cases, with humour:
WhatsApp also argues that it cannot share information, because its encrypted communications mean “only you and the person you’re communicating with can read what is sent”.
Technology commentators suggest regular interruptions to service could dent WhatsApp’s popularity.