Root Failed with Kingo Android Root

Generally, there are two reasons:

1. There is no available exploit for your device. Android version above 5.1 is not supported by Kingo for now.
2. Bootloader is locked by manufacturer. With a locked bootloader, there is nothing Kingo could do to root your device.
   Bootloader is the first to execute when an Android device is turned on, which is responsible for verifying the integrity of and launching the operating system. It prevents users from modifying the system. The modification for permanent root access requires bootloader being unlocked.
   

Here are some suggestions:

1. Wait and stay tuned with Kingo update. And try it out with every new version released.
2. Unlock your bootloader and try again.
3. Google "how to root + your device model" and find some resolution manually. Be carefully when it requires to flash a custom recovery.