[Buildah] 'overlay' is not supported over overlayfs

Dear buildah community, we are just trying to create a container image inside an unprivileged container using buildah, however this process fails as shown below: $ buildah bud -f Dockerfile --format docker -t $IMAGE_NAME 'overlay' is not supported over overlayfs, a mount_program is required: backing file system is unsupported for this graph driver any idea what we are doing wrong? thank you