stuck on boot logo ( before anything animate )

I have galaxy s6 G920F and I can't return to stock ROM, if I flash via Odin android 5.1.1, it says successful then stops on boot screen. I also did factory rest after installing also cleared cache but nothing happens. I tried France stock ROM 5.1.1 XEF I guess also UK BTE but I got same results.. but I can install custom ROM and it works fine but I need to return my phone but can't until it's on stock ROM.

It also says dm-verity verification failed. I just need to boot with stock ROM other error or warning messages don't matter..

Any help please thanks.