iOS App Store
HQ Trivia stopped appearing in the iOS App Store because of a technical issue. Pxhere

HQ Trivia, a popular live trivia app that gives winners cash prizes, suddenly went missing Monday morning from the iOS App Store.

Adam Blacker, communications lead at app analytics firm Apptopia, first noticed HQ Trivia’s absence in Apple’s official App Store after realizing the game suddenly stopped receiving downloads.

Reports indicated that the app was not available for most users searching the United States version of the App Store. HQ Trivia did appear to still be available in the United Kingdom App Store, and the app remains available for Android through the Google Play Store.

According to Mashable, the sudden disappearance of HQ Trivia from the App Store was the result of an innocuous mistake: the credit card associated with the HQ Trivia developer’s account expired and wasn’t updated. As a result, the app was temporarily made unavailable until the issue was resolved.

HQ Trivia was developed by Intermedia Labs, the makers of Hype—a live streaming video app—and music and video remix app Bounce. It is not clear if Hype or Bounce were also temporarily removed from the App Store during the period HQ Trivia was removed.

Users who already have HQ Trivia installed on their device likely didn’t notice the issue; while the app was pulled from the App Store, it continued to function normally for those who already had the app on their device.

While the app continued to work for most users, its absence from the App Store meant new users couldn’t join in the fray and compete in the trivia game. It also meant that Intermedia Labs wasn’t able to push out an update to users with the app, which could have resulted in bugs and flaws in the app going unpatched—though there is no indication that Intermedia Labs had an update planned during the app’s brief disappearance from the App Store.

HQ Trivia has been a wildly popular success with its twice-a-day, live trivia contests that reward cash prizes to the winners who answer every question correctly. The app reportedly had 1.8 million simultaneous users who tuned in to play the trivia game on Sunday and compete for a $25,000 prize.