1. Take it back to your service counter for them to reflash.
2. Rooting is one of those non-support areas. Get back to who supports Kingroot and ask how to recover.
i turned powered off my Samsung galaxy J2 prime then tried to turn it back on and it says custom binary blocked by frp and under it in small red letters it says SECURE FAIL : KERNEL. How do i fix i used king-root to root device and wiped off the programming to my phone please respond and help me fix problem.