IOS App restart when selecting "learn new words"

I am having a problem when I start “learn new words” in the last lesson of the French language course #3. The IOS app restarts every time I try.

Has anyone got an idea what I can do?

Kind Regards

John

it was working smooth on my iPad Pro when it was running on ios 10 however as I have updated to ios 11.3 whenever now I am opening the app it only loads a blank screen on the start up and crashes after a while automatically. How do I fix it?

with regrads