The most important new Apple Watch feature has been shut down in China (AAPL)

There is no carrier currently offering service for the Apple Watch Series 3 with LTE in China.
A cellular connection is the biggest new feature on this year's Apple Watch.
The Chinese government could be looking to more closely regulate the eSIM technology the device uses.

The single wireless carrier supporting Apple's latest Apple Watch in China has ceased offering service for the device, the Wall Street Journal reported on Thursday.

China Unicom, one of three state-owned wireless carriers, initially offered cellular service for the Apple Watch Series 3 with LTE, but stopped supporting it on September 28, according to the report.

In the United States, the LTE Apple Watch is supported by all four major carriers for an additional charge of $10 per month. LTE service is the primary new feature on this year's Apple Watch model.

One reason why China Unicom may have stopped service is because Apple uses a new kind of SIM card in the Apple Watch, called eSIM. Chinese regulators may be slowing adoption to figure out the policy around eSIM cards, which are built into the watch.

Apple does not reveal Apple Watch sales numbers but several analysts believe the Apple Watch 3 is gaining momentum and is poised to be a hit, partially due to the new cellular version of the device.

"Roughly 80% of consumers we have polled that are interested in the Watch are buying the new LTE/cellular version as this looks to be a major selling point for Apple Watch sales vs. prior versions given its new standalone product offering," GBH Insights analyst Daniel Ives wrote about United States-based polls in a research note on Wednesday.

UBS analysts analyzed Google search trends for the new model of the Apple Watch and based on that data and other trends, forecast 19% year-over-year growth in Apple's "Other" products category, which is how the company reports Apple Watch revenue.

"The Apple Watch appears to be gaining traction, with interest in the Series 3 around its announcement greater than for the Series 2, in all geographies," UBS analyst Edward Yen wrote.

The lack of cellular service could cool interest in the new Apple Watch in China, and could raise fears again that the Chinese government is looking to more deeply regulate Apple, which has caused the Apple stock to drop in the past.