diff --git a/ops/nixos/lib/baserow.nix b/ops/nixos/lib/baserow.nix
index 89176f04f1..17ffba58f3 100644
--- a/ops/nixos/lib/baserow.nix
+++ b/ops/nixos/lib/baserow.nix
@@ -202,6 +202,7 @@ in
       non_smtpd_milters = ${config.services.opendkim.socket}
     '';
   };
+  users.users.postfix.extraGroups = [ "opendkim" ];
   services.opendkim = {
     enable = true;
     domains = "csl:baserow.lukegb.com";