Supreme Court judge Alexandre de Morais said the company had “cheated” in reactivating some users’ access.
He fined X and Musk’s other company, internet satellite company Starlink, more than $920,000 (£695,000) for each day X operated in Brazil.
But it is unclear whether the court can enforce the fine. Musk’s company has previously ignored Brazilian court orders, including one that resulted in the social media site being banned in August.
X explained that a change in network provider resulted in “a temporary service restoration for Brazilian users in error” due to some users suddenly losing connectivity on Wednesday.
“While we anticipate that access to this platform will soon be unavailable in Brazil, we are working with the Brazilian government to restore access for Brazilians as soon as possible,” an X spokesperson said in a statement.
The company’s explanation surprised some observers.
“Everything that happened during the day leads us to believe that it was intentional,” said Basilio Rodriguez Perez, general counsel for ABRINT, the nation’s largest trade group for Internet service providers (ISPs).
ABRINT said X had moved to a server hosted by Cloudflare, and that the site appeared to use a dynamic Internet Protocol (IP) address that constantly changes, indicating that the change in access for Brazilian users was intentional.
In contrast, older systems relied on specific IP addresses that could be more easily blocked.
These dynamic IP addresses could be connected to critical services within Brazil, said ABRINT advisory board member Basilio Rodriguez Perez.
“Many of these IPs are shared with other legitimate services, such as banks and large internet platforms, so it is impossible to block them without affecting other services.”
This includes the PIX service, which millions of Brazilians use for digital payments.
Despite these changes, some experts say Cloudflare is well-positioned to help enforce Brazil’s ban.
“In fact, I think the ban would be more effective if CloudFlare actually cooperated with the government,” said Felipe Autran, a constitutional lawyer in Brasilia.
“I think so because they are a huge supplier to a lot of companies and governments in Brazil.”
Cloudflare declined to comment when contacted by the BBC.
