diff --git a/nixos/modules/services/mail/nullmailer.nix b/nixos/modules/services/mail/nullmailer.nix
index 09874ca0ed75..f9c345669978 100644
--- a/nixos/modules/services/mail/nullmailer.nix
+++ b/nixos/modules/services/mail/nullmailer.nix
@@ -220,7 +220,7 @@ with lib;
       after = [ "network.target" ];
 
       preStart = ''
-        mkdir -p /var/spool/nullmailer/{queue,tmp}
+        mkdir -p /var/spool/nullmailer/{queue,tmp,failed}
         rm -f /var/spool/nullmailer/trigger && mkfifo -m 660 /var/spool/nullmailer/trigger
       '';