Hello,
Do you run the build in a restricted environment that doesn't have access to public registries? Do you have configured some private registries in your Docker configuration?
If possible, could you run the following commands (it's almost the same skopeo command referenced in the k3s recipe) and let us know what output you get:
$ bitbake k3s -c devshell
$ skopeo --debug --override-arch arm64 copy --additional-tag="docker.io/rancher/mirrored-pause:3.5" \
docker://rancher/mirrored-pause:3.5 docker-archive:mirrored-pause-test.tar
Best regards,
George