diff --git a/nixos/modules/issuer.nix b/nixos/modules/issuer.nix
index 3ec5a1471e7a6b99a01362f5dff48599e75f2812..451901ac3b13959d433b50ad82060336c2cda104 100644
--- a/nixos/modules/issuer.nix
+++ b/nixos/modules/issuer.nix
@@ -2,7 +2,7 @@
 # ZKAPs.
 { lib, pkgs, config, ... }: let
   cfg = config.services.private-storage-issuer;
-  zkapissuer = import ../pkgs/zkapissuer {};
+  zkapissuer = pkgs.callPackage ../pkgs/zkapissuer { };
 in {
   imports = [
     # Give it a good SSH configuration.