TouchID not working to purchase our app on some devices

Hi, our app allows users to purchase InApp subscriptions.


During out testing we see the fingerprint (TouchID) purchase confirmation for most devices but some devices show the account password request screen even though the device has TouchID enabled for iTunes and App Store and test purchases for other apps shows the fingerprint confirmation as expected


These devices are using the officially relased App Store version of the app, not a development or TestFlight version.


Can anyone suggest why our app would show the password prompt instead of the TouchID prompt for certain devices even though TouchID should be enabled?


Thanks!