Is there any way to know the cause I cannot install app from Google Play I'm using Sony Xperia S (also I have old SE Xperia X10 Mini) and want to install mytaxi app. But Google Play says that I'm not eligible to do this and I do not understand why! I've found an apk in the internets and it works fine, but I want to know the reason and have updates.
This problem is rather frequent and only the developers can fix it.

Reason is probably that the app wants features like GPS, certain screen sizes or a minimum Android version. One of those requirements is not met although it runs just fine.

So the obvious way to get this fixed is to contact the developers and have them relax that declaration..