“Sorry, TikTok isn’t available right now,” the message read.
Hours before a federal law banning TikTok from the United States was set to take effect, the social media app went dark, and U.S. users could no longer access videos on the platform. Instead, the app greeted them with a message that said “a law banning TikTok has been enacted.”
“We are fortunate that President Trump has indicated that he will work with us on a solution,” the message said. “Please stay tuned!”
The app also appeared to have been removed from Apple’s U.S. app store, some users said.
TikTok became unavailable after the Supreme Court decision on Friday upholding the law, which calls for TikTok’s Chinese owner ByteDance to sell the app by Sunday or otherwise face a ban. The law had overwhelmingly passed Congress last year and been signed by President Biden. TikTok, which has faced national security concerns for its Chinese ties, had expected to win its legal challenge to the law, but failed.
The blackout capped a chaotic stretch for TikTok, which had made last-minute pleas to both the Biden administration and President-elect Donald J. Trump for a way out of the law. Until Saturday night, no one — including the U.S. government — was entirely sure what would happen to it when the law took effect. The United States has never blocked an app used by tens of millions of Americans essentially overnight.
The law has a provision to penalize app store operators like Apple and Google, and internet hosting companies like Oracle for distributing or maintaining the TikTok app. Under the law, those companies face penalties as high as $5,000 per user who can access the app.
For TikTok and ByteDance, the developments are a major blow. TikTok has roughly 170 million users in the United States, who are some of the app’s most lucrative customers. In legal filings, TikTok has said that even a temporary disappearance could kneecap it, with users and creators leaving for other platforms and never returning even if a ban was lifted.
The situation was further complicated by the law’s start date falling in the final days of Mr. Biden’s presidency. A White House spokeswoman suggested on Saturday that the Biden administration would not start fining companies on Sunday.
“We see no reason for TikTok or other companies to take actions in the next few days before the Trump administration takes office on Monday,” Karine Jean-Pierre, the White House press secretary, said in a statement. “We have laid out our position clearly and straightforwardly: actions to implement this law will fall to the next administration.”
Mr. Trump said on Saturday he would “most likely” find a way to give TikTok a 90-day extension once he takes office on Monday. The law gives the president the ability to extend the deadline for a sale only if there is “significant progress” toward a deal that would put TikTok in the hands of a non-Chinese owner. It was not clear how that extension might work if the ban had already taken effect.
On Saturday, the mood on TikTok was somber. Alix Earle, a content creator with 7.2 million followers who rose to fame on the app in 2022, posted tearful videos mourning the platform.
“I feel like I’m going Through heartbreak,” Ms. Earle wrote in one video. “This platform is more than an app or a job to me. I have so many Memories on here. I have posted every day for the past 6 years of my life. I’ve shared my friends, family, relationships, personal struggles, secrets.”
Ms. Earle added that she had been “in denial” about the ban.
Other users spent their final moments on the app recreating viral dances of years past. The “For You” page filled with montages of users’ all time favorite trends and songs, many dating back to the early days of the pandemic, when the app soared in popularity.
By 9 p.m. Eastern on Saturday night, TikTok was showing U.S. users a pop up message that said the app would soon stop working.
It said the law would “force us to make our services temporarily unavailable.”