I'm using Ubuntu 20.04.5 with an 11th Gen Intel® Core™ i7-1195G7 @ 2.90GHz × 8.

After cloning the plutus-apps repo and setting my nix config, i can't get pass the following nix-shell error:

trace: To materialize project.plan-nix for haskell-project entirely, pass a writable path as the `materialized` argument and run the 'updateMaterialized' script in 'passthru'.
warning: error: unable to download 'https://hydra.iohk.io/nix-cache-info': Timeout was reached (28); retrying in 280 ms

my etc/nix/nix.conf is set to the parameters from README.adoc :

substituters        = https://hydra.iohk.io https://iohk.cachix.org https://cache.nixos.org/
trusted-public-keys = hydra.iohk.io:f/Ea+s+dFdN+3Y/G+FDgSq+a5NEWhJGzdjvKNGv0/EQ= iohk.cachix.org-1:DpRUyj7h7V830dp/i6Nti+NEO2/nhblbov/8MW7Rqoo= cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY=
extra-experimental-features = nix-command flakes 

any advice appreciated


The compilation with nix-shell completed bringing me to


However, along the way I get lots of warnings. Should I be concerned? For example:

System/Remote/Snap.hs:7:1: warning: [-Wunused-imports]
    The import of ‘<$>’ from module ‘Control.Applicative’ is redundant
7 | import Control.Applicative ((<$>), (<|>))
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

2 Answers 2


The nix cache is now located at cache.iog.io

With a /etc/nix/nix.conf (or ~/.config/nix/nix.conf) that looks like this:

experimental-features = nix-command flakes
allow-import-from-derivation = true
substituters = https://cache.nixos.org https://cache.iog.io
trusted-public-keys = hydra.iohk.io:f/Ea+s+dFdN+3Y/G+FDgSq+a5NEWhJGzdjvKNGv0/EQ= cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY=

then you should have the binary cache from IOG working again. (you many need to log out and log back in and or restart the nix daemon to get these changes to take)

Doc source

  • thanks. So the nix-shell has been running for over an hour now. should it be taking so long?
    – tyvan266
    Commented Dec 4, 2022 at 3:32
  • It depends on what is specified in the shell.nix but that doesn't sound like a good sign. If you can build and run the cardano node as per these commands in a few min you are pulling from the cache. You should also be able to see cache.iog.io in the output from nix. Rebooting is also a sure fire way to make sure the new config has applied.
    – 21eleven
    Commented Dec 4, 2022 at 17:19

You need to replace hydra.iohk.io with cache.iog.io, as the hydra server has been decommissioned.

Leave the key as it is: f/Ea+s+dFdN+3Y/G+FDgSq+a5NEWhJGzdjvKNGv0/EQ=.

  • thanks! however now i'm getting the error: ``` warning: ignoring untrusted substituter cache.iog.io ```
    – tyvan266
    Commented Dec 3, 2022 at 20:59
  • I resolved the issue by changing substituter to trusted-substituter
    – tyvan266
    Commented Dec 3, 2022 at 21:28

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