Apple News has one, major issue: No one knows how many people are actually reading its content.

Apple’s senior vice president of Internet software and services admitted to the Wall Street Journal in an interview published on Sunday that Apple doesn’t “know what the right number is” on Apple News traffic. He said that the company is working on the glitch, but added that the traffic count Apple has been presenting to publishers is “lower than reality.”

Not knowing exactly how many people are reading stories on Apple News is a critical issue for publishers and Apple alike. Traffic ultimately dictates how much revenue can be generated on the ads sitting around the stories. If publishers, marketers, and even Apple has no idea how many people have read a particular story, there’s no way to assign a proper advertising rate.

Apple AAPL unveiled Apple News at the Worldwide Developers Conference last year. The platform, which launched with iOS 9, is designed to share news from publishers all over the world. When users start up the app, they can quickly start reading content. The app is essentially a feed for users to read the news stories they care about. Cue told the Journal that over 100 publishers, including Fortune publisher Time Inc. TIME , have signed on to Apple News. He claims that 40 million people have at least tried out the app, but did not say how many people use it on a regular basis.

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Declaring that 40 million people have so far used Apple News may not do much to reassure publishers that may already be gun-shy about Apple News. Apple has, after all, sold more than 1 billion iOS devices. That said, Apple News is only available in the U.S., U.K., and Australia, and requires iOS 9, so many of those devices will not qualify.

Cue’s acknowledgement that Apple isn’t clear on how many people are actually using his company’s News platform is perhaps not surprising to publishers. Last year, Time Inc. CEO Joe Ripp said that he was “disappointed by the ad revenue” coming from Apple News, adding that the traffic it was generating was somewhat underwhelming. A few unidentified publishers told Digiday in November that they, too, were “disappointed” by Apple News.

WATCH: For more on Apple News, check out the following Fortune video:

“We got delayed data on usage, and it’s still very limited, and selling ads isn’t easy,” one unidentified executive said of Apple News.

Now that Apple has said that it has been unable to accurately evaluate traffic, it could make it more difficult for the company to make it in what is an increasingly competitive marketplace. Facebook FB has an alternative news vehicle, called Instant Articles, that’s designed to provide the latest news to its more than a billion users. Snapchat, the company that became popular for a platform that allows content to self-destruct, is also competing in the market.

Those services, along with Apple News, represent an attempt by the companies to keep users engaged with their platforms. They reason being that the more people rely on them to get their news, the more likely they’ll be to stay with the respective services. In the case of Apple News, it’s all about keeping customers on iOS, rather than switching to Android. Indeed, Apple allows publishers to take 100% of the advertising revenue, if they deliver the ads themselves. Only those publishers that rely on Apple’s iAd need to hand over 30% of the revenue to Apple.

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Still, getting off to such a troubled start is not good for Apple, and Cue made clear in his talk with the Journal that his company is actively working at fixing its issues. He didn’t provide a timeline on when Apple would finally know exactly how many users are reading content on the app.

Apple did not respond to a request for comment.