Exchange email verification fail

Hi, I'm Nic, I have got a iphone 6s plus 128GB, IOS 9.0.2. i have backup in icloud from 6 plus - 6s plus, when i get back the back up to 6s plus, i found the Exchange Email which i always using cannot login, when i type the password in login data, it hold.....someone can help me? Many Thanks!!