This is not an implementation issue with RevenueCat, but rather an issue of the card being declined, no card on file, unsupported country, etc.
That’s fairly common for trials on Play Store apps. 50–60% is about average, and (anecdotally) less than 30-40% is very uncommon on the low end.
If you segment your trials by country you might find the effect more dramatic outside of the US which may be a signal of the same thing (some countries allow users to start a trial without a payment method).
In terms of what to do about it, one option would be that you implement a campaign in their app where if a subscriber has a trial in a billing retry state they…
- Receive a push notification instructing them to update their payment details
- Or receive an in-app message recommending the same
- And then ideally have that in-app message include a CTA directing the subscriber right to the Play Store to update that information so you don’t lose customers in the “funnel” from the app to that page.