What just happened? While China blocks a number of western websites—Facebook, Twitter, etc.—Microsoft’s Bing was allowed through the Great Firewall thanks to its censored search results. But despite kowtowing to the government, the search engine has joined the list of inaccessible services.

“We’ve confirmed that Bing is currently inaccessible in China and are engaged to determine next steps,” said Microsoft. According to the Financial Times, state-owned telecoms company China Unicom confirmed the government ordered the block on Bing.

When Google pulled out of China in 2010 over censorship and cyberattack concerns, Bing, which censors sensitive topics such as Tiananmen Square, was left as the only major foreign search engine that could be accessed in the country.

It appears that Bing has been banned using a DNS corruption—a popular method of blocking websites in China. It means Chinese nameservers are unable to retrieve the IP address of a URL. TechCrunch notes that some people have been able to access Bing by typing in the IP address directly.

The reasons behind the ban are unclear. It follows increased tensions between the US and China, from the ongoing trade war to the battle with Huawei and the arrest of its CFO.

Google had faced controversy over a possible return to China with a censored version of its search engine, known internally as Project Dragonfly. But objections from employees and US politicians led to its reported cancelation last month. It’s said to be still studying the idea, though the Bing incident may influence Google's decision.

Bing is reported to have accounted for just 2 percent of the Chinese market, way behind local search engines Baidu and Sogou, but that’s not to say Microsoft won’t feel aggrieved by the ban.