Facebook ads - no downloads for IOS app even though i generate 200 clicks

I have recently launched an app on IOS and Android. I use the exact same targeting and pictures for both campaigns taht i run on facebook.

I get a 4 to 1 click to install ratio on android and absolutely 0 downloads on IOS even though i generated more than 200 clicks. The latest facebook SDK was implemented and double checked. all good on this side.

Any idea what could be the problem ? Could a loss of keychain (due to the switch from one developers account to another) be the source of the issue?

Looking forward to your feedback. Im really stuck here ...

Thanks