IMO app is not working properly in my iphone 6S

Hello,

My name is Akhilesh. am living in Saudi Arabia i brought iPhone 6S almost 9 months ago. From that time IMO app is not working properly in my phone. Then i updated now ios 10 but still same problems. Then i uninstalled the app and try to reinstall the app but unfortunately i can’t reinstall this app the verification code is not sending from my iPhone 6S. Please fix this problem as soon as possible.

Thank you