LinkedIn has been the lone major American social network allowed to operate in China. To do so, the Microsoft-owned service for professionals censors the posts made by its millions of Chinese users.

Now, the Sunnyvale-based platform is in hot water for not censoring enough.

China’s internet regulator rebuked LinkedIn executives earlier this month for failing to control political content, according to three people briefed on the matter. Though it isn’t clear precisely what material got the company into trouble, the regulator said it found objectionable posts circulating in the period around an annual meeting of China’s lawmakers, said these people, who asked for anonymity because the issue isn’t public.

As a punishment, the people said, officials are requiring LinkedIn to perform a self-evaluation and offer a report to the Cyberspace Administration of China, the country’s internet regulator. The service was also forced to suspend new sign-ups of users inside China for 30 days, one of the people added, although that time period could change depending on the administration’s judgment.

The CAC did not immediately respond to a faxed request for comment.

LinkedIn’s presence in China has long drawn interest across Silicon Valley as a potential path into the country’s walled-off internet, home to the world’s largest group of web users. The punishment underscores deep divisions between the United States and China over how the internet should work.

For years, China’s government has blocked major U.S. services like Facebook, Twitter and Google over its inability to control what is posted there. In Washington, critics say such barriers are symptomatic of China’s unwillingness to follow global norms governing the internet and technology more broadly.

LinkedIn’s China service, which has more than 50 million members, makes it vulnerable to tensions between the two powers. The run-in with the regulator came just weeks before Thursday’s scheduled meeting between Chinese and American officials in Alaska, the first face-to-face sit down of the Biden administration.

Competition over technology has been a key sticking point between the two countries.

The Biden administration has said it will turn to allies to help pressure China on tech policies it deems unfair.

Chinese officials have pushed new plans for technological self-reliance, which involve developing its own versions of everything from computer chips to jetliners.

Anxieties in Washington were recently heightened by a hack that Microsoft has tentatively linked to China aimed at businesses and government agencies that used the company’s email services. On March 9, LinkedIn posted a statement saying it had “temporarily” stopped registering new users in China.

“We’re a global platform with an obligation to respect the laws that apply to us, including adhering to Chinese government regulations for our localized version of LinkedIn in China,” the statement added.

Local Chinese firms regularly endure similar scoldings, indicating how difficult it can be to navigate an internet market characterized by ever-tightening speech controls.

On the Chinese internet, an agreement to censor doesn’t guarantee smooth sailing for any firm, foreign or local.

When it first announced it would be opening a Chinese site nearly seven years ago, LinkedIn drew curiosity from a U.S. internet industry perennially banned by the country’s Great Firewall, as China’s censorship system is nicknamed. To ensure its presence, LinkedIn sold a stake to well-connected Chinese venture capital partners and pledged to follow local laws, including censorship guidelines.

The company has used a combination of software algorithms and human reviewers to flag posts that could offend Beijing.

Users who run afoul of the speech rules have generally received emails informing them that their post is not viewable by LinkedIn members in China.

Its early efforts drew ire from users whose content was blocked even if they had been posting from outside the country. Still, unlike its peers, LinkedIn has remained in China and offered a tantalizing case study in market access.

That perseverance hasn’t always translated into success. LinkedIn has had a hard time competing with WeChat, the ubiquitous Chinese chat and social media service, and remains a relatively small player.

The environment has become more difficult, too. Since he took the reins of the Communist Party in late 2012, Xi Jinping, China’s leader, has implemented a series of crackdowns on the internet. Xi’s policies have also called for deeper economic self-sufficiency and eschewing Western culture, a blow to a service whose appeal has been to connect Chinese professionals to the world.

Xi has presided over the rising power of the CAC, the regulator that punished LinkedIn. It has become a de facto ministry of censorship, poring over memes across the country’s internet, and calling for takedowns when companies’ censors miss something.