Vyos 1.2 build failed

I am trying to rebuild kernel for vyos 1.2 as described here https://wiki.vyos.net/wiki/Rebuild_VyOS_kernel_Step#VyOS_1.2.x but make iso command is failing with erro chroot: “failed to run command ‘/usr/bin/env’: No such file or directory”

I am also trying it using vyos-build docker but docker pull command is failing with error “Error response from daemon: manifest for vyos/vyos-build:latest not found” and docker building is failing with error " Failed to connect to raw.githubusercontent.com port 443: Connection timed out"

I am able to pull docker pull vyos/vyos-build:crux but inside that docker ./configure cmd is failing with “bash: ./configure: No such file or directory”

How Can I rebuild kernel for vyos 1.2 version and create iso using that?