guest agent connection lost: nix config build failed: exit=1 error=None output=unpacking 'github:numtide/nixpkgs-unfree/accc1f937187d1bf7a74609e8c0a784f579b5dd5' into the Git cache... unpacking 'https://channels.nixos.org/nixpkgs-unstable/nixexprs.tar.zst' into the Git cache... copying path '/nix/store/rhsxvv1380jmchb5p3a43d24mhlmp2ry-source' from 'http://127.0.0.1:10500'... error: … while calling the 'derivationStrict' builtin at «nix-internal»/derivation-internal.nix:37:12: 36| 37| strict = derivationStrict drvAttrs; | ^ 38| … while evaluating derivation 'nixos-system-spindle-microvm-26.05pre-git' whose name attribute is located at /nix/store/bmwp8va0bazc5v3vybl00nm1p9z9ah56-9figz32vbiblaw5x3li1hc8q9qwlwf27-source/pkgs/stdenv/generic/make-derivation.nix:647:11 … while evaluating attribute 'buildCommand' of derivation 'nixos-system-spindle-microvm-26.05pre-git' …