lenovo A6020a46 giving error code 7 for oreo 8.1

lenovo A6020a46 giving error code 7 for oreo 8.1
5.0 1

#1

When i tried to install oreo rom for lenovo A6020a46 it gives error 7.
I tried all the released versions, no luck. I have no problems with nougat. Please help.