LinkedIn was the only major American social network allowed to operate in China. To this end, Microsoft’s proprietary service for professionals is censoring the contributions of millions of Chinese users.

Now it’s in hot water because it’s not censored enough.

China’s Internet regulator reprimanded LinkedIn executives earlier this month for failing to control political content, according to three people who were briefed on the matter. Although it is not exactly clear what material got the company into trouble, the regulator said it found illegal sites around an annual meeting of Chinese lawmakers, said people asking for anonymity because the issue was not public .

As a punishment, LinkedIn officials demanded that LinkedIn perform a self-assessment and submit a report to the Cyberspace Administration of China, the country’s internet regulator. The service has also been forced to suspend new user registrations in China for 30 days, one respondent added, although this period could change depending on the administration’s judgment.

The Cyberspace Administration of China did not immediately respond to a faxed request for comment.

LinkedIn’s presence in China has long piqued interest across Silicon Valley as a potential route into the country’s foreclosed internet, home to the world’s largest group of web users. The punishment underscores the deep divide between the United States and China over how the internet is supposed to work.

For years, the Chinese government has blocked important US services such as Facebook, Twitter and Google because it cannot control what is published there. In Washington, critics say such obstacles are symptomatic of China’s unwillingness to follow global norms for the Internet and technology in a broader sense.

LinkedIn’s China service, which has more than 50 million members, makes it vulnerable to tension between the two powers. The regulatory meeting took place just weeks before the scheduled meeting between Chinese and American officials in Alaska on Thursday, the Biden government’s first face-to-face meeting.

The competition for technology was a crucial sticking point between the two countries. The Biden government has announced that it will turn to allies to press China to adopt what it considers to be unfair technology policies. Chinese officials have pushed new plans for technological self-sufficiency that include developing their own versions of anything from computer chips to jetliners.

Washington fears were recently heightened by a hack Microsoft tentatively linked to China targeting businesses and government agencies that use the company’s email services.

On March 9, LinkedIn released a statement that new user registrations in China have been “temporarily” suspended. “We are a global platform with an obligation to respect the laws that apply to us, including complying with government regulations for our localized version of LinkedIn in China,” the statement added.

Local Chinese companies regularly endure similar scolding, indicating how difficult it can be to navigate an internet market characterized by increasingly stringent language controls. On the Chinese Internet, a censorship agreement does not guarantee smooth sailing for businesses, foreigners, or locals.

When LinkedIn announced the opening of a Chinese website nearly seven years ago, it was curious about a US internet industry that the country’s Great Firewall has consistently banned because of China’s censorship system. To ensure its presence, LinkedIn sold a stake to well-connected Chinese venture capital partners and pledged to comply with local laws, including censorship guidelines.

The company used a combination of software algorithms and human reviewers to flag posts that could offend Beijing. Users who violate the language rules have generally received emails informing them that their post will not be visible to LinkedIn members in China.

His early efforts met with annoyance from users whose content was blocked even if posted from outside the country. Unlike its colleagues, LinkedIn stayed in China and offered an exciting case study on market access.

This persistence has not always led to success. LinkedIn has struggled to compete with WeChat, the ubiquitous Chinese chat and social media service, and remains a relatively small player.

The environment has also become more difficult. Since he took over the leadership of the Communist Party in late 2012, China’s leader Xi Jinping has carried out a series of raids on the Internet. Mr. Xi’s policies also called for deeper economic self-sufficiency and the avoidance of Western culture, a blow to a service whose appeal was to connect Chinese professionals with the world.

Mr. Xi has led the emerging power of the Cyberspace Administration of China, the regulator that penalized LinkedIn. It has grown into a de facto censorship department, pondering memes and complaints on the country’s internet, and calling for shutdowns when corporate censors miss something.