Try fix nixosmodule

nix/nixos-module.nix

@@ -2,7 +2,6 @@
   config,
   lib,
   pkgs,
-  inputs,
   ...
 }:
 
@@ -17,7 +16,7 @@ in
 
     package = mkOption {
       type = types.package;
-      default = pkgs.callPackage ./package.nix { inherit inputs; };
+      default = pkgs.callPackage ./package.nix { src = ../server; };
       description = "The systant package to use";
     };