diff --git a/nixos/modules/services/mail/postfix.nix b/nixos/modules/services/mail/postfix.nix
index 86b9223eb604..7b2ef9e1d2fd 100644
--- a/nixos/modules/services/mail/postfix.nix
+++ b/nixos/modules/services/mail/postfix.nix
@@ -972,7 +972,7 @@ in
             ${lib.concatStringsSep "\n" (
               lib.mapAttrsToList (to: from: ''
                 ln -sf ${from} /var/lib/postfix/conf/${to}
-                ${lib.getExe' cfg.package "postmap"} -o -p /var/lib/postfix/conf/${to}
+                ${lib.getExe' cfg.package "postmap"} /var/lib/postfix/conf/${to}
               '') cfg.mapFiles
             )}