It is becoming increasingly difficult for us to include new features and improve performance while still supporting iOS9. The most recent release won't play videos on some iOS 9 devices.
What can you do?
First of all, see if you can update. The current version of iOS is iOS 13, so you're several years behind.
If you can't update. For now, the only way we can support your device to provide you with an older version via Apple's Testflight.
This gives you access to Beta versions. In this case using an old one will save your problem, plus give you access to any improved versions we can create for you in the future that include special iOS 9 workarounds to keep FulGaz functioning on your iPad while providing improved performance on newer devices.
UPDATE: We have currently managed to get this working again, but we cannot guarantee how much longer we can support iOS 9 and older devices.