Build mainnet-byron-proxy failed

[freddieee]

Sytem: Ubuntu 18.04

Command: nix-build -A scripts.mainnet.proxy -o mainnet-byron-proxy

Error log:
trace: Using index-state: 2020-01-31T00:00:00Z for cardano-byron-proxy building '/nix/store/p02j0924vd4svr4n1g8laxzl2c3vf9xp-happy-plan-to-nix-pkgs.drv'... error: moving build output '/nix/store/mzi2s0fscckbqz3bjmpjpami8zssygym-happy-plan-to-nix-pkgs' from the sandbo x to the Nix store: Permission denied (use '--show-trace' to show detailed location information)

I tried that sudo chmod 777 /nix, but it still doesn't work.

I think you need to change the owner of the folder: chown -R nix:nix /nix provided the user who builds is called nix.