nix ledger build

gistfile1.txt

fetching path ‘/nix/store/aa8184zja11630nayzgdpjyc4skmlz7c-expat-2.1.0’...

*** Downloading ‘http://zalora-public-nix-cache.s3-website-ap-southeast-1.amazonaws.com/aa8184zja11630nayzgdpjyc4skmlz7c.nar’ to ‘/nix/store/aa8184zja11630nayzgdpjyc4skmlz7c-expat-2.1.0’...
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0curl: (7) Failed to connect to zalora-public-nix-cache.s3-website-ap-southeast-1.amazonaws.com port 80: Connection refused
/nix/store/ni1rbgsw9jv5iijj1igwp423j7vr30v7-xz-5.0.7/bin/xz: (stdin): File format not recognized
error: unexpected end-of-file
download of ‘http://zalora-public-nix-cache.s3-website-ap-southeast-1.amazonaws.com/aa8184zja11630nayzgdpjyc4skmlz7c.nar’ failed: No such file or directory
could not download ‘/nix/store/aa8184zja11630nayzgdpjyc4skmlz7c-expat-2.1.0’ from any binary cache
fetching path ‘/nix/store/aa8184zja11630nayzgdpjyc4skmlz7c-expat-2.1.0’ failed with exit code 1
fetching path ‘/nix/store/jk6130sfnnpnpd22bai77acbk93lmlm3-clang-wrapper-3.5.0’...
killing process 95844
error: some substitutes for the outputs of derivation ‘/nix/store/wkjnl3wf3zwvcin9c7f3aamxa4icfrdp-expat-2.1.0.drv’ failed (usually happens due to networking issues); try ‘--fallback’ to build derivation from source