Soft brick e5 play only fastboot

I have a e5 play now it stuck at fastboot mode
Cant boot, it report failed to validate boot image.
I try to flash stock rom but it report secure downgrade
My model xt1921-2 cid 50.
First dont know i have to check cid to flash. So i flashed cid1 rom. And now i cant flash cid50 rom :(
Can anyone help me. Maybe find a latest cid50 rom first. I tried 91-121-19 rom