Onedrive app will not allow to open

iOS 9.3.1 - Onedrive app will not open. I have restarted my iPhone 5s and have tried to open the app by clicking on "open" but problem is not resolved. The app in my lock screen is shaded as if the app was updating but not reflecting update in App Store. It's as if the Onedrive app is frozen and will not allow me to open the app. Please help me resolve this issue.

Thanks, RShamsie