Can't launch app on iPad using appium

Hello

I have a set of working appium tests for iPhones and Android devices.
I am trying to run these tests on iPad devices and i get an exception trying to launch the app (driver.launchApp())
I am using appium 1.4 .
Any ideas on what can cause this issue?
Is it regarding iPad version ? (i am using iOS >= 8)

Thanks in advance

What is the error you are receiving? Have you inserted the correct UDID? Have you declared the correct capabilities?

yes
it’s the correct udid , tried again with a newer iPad 3 and got the same “java.lang.reflect.InvocationTargetException” exception when trying to launch the app.
the launch works well when i try to do the same thing in xcode’s instruments

Are you using the correct build for the physical device, not the one for the simulator?