Your organization email works fine. After several hours of use, the device requests an encryption to your device. You checked by visiting Settings > Security. It is shown that your device is encrypted. You follow the Android to encrypt the device, but have no luck. The device still requests the encryption process although is already encrypted.
The root cause of this problem is on Android Lollipop device. On Android Lollipop, the device is already encrypted, but the encryption is should be verified. Some people also found this issue when upgrading from Kit Kat to Lollipop. The problem happens on work email that has additional policy from the administrator such as Office 365 or Exchange. Please notes, that this issue only happen on Lollipop and is not because Office 365.
The problem can be solved by following these steps:
- Select Settings > Lock Screen
- Choose Screen Lock
- Insert your current PIN
- On the choose screen lock, choose PIN
- Select "Require PIN to start device"
- Setup your PIN (you can change it if you want)
- Confirm your PIN (put the same PIN with the previous one)
- And select "Don't show notification at all"
- Done, you can add and remove your email account if necessary. Mine automatically works after that