diff --git a/backup.nix b/backup.nix
index cc045cf..38ec82a 100644
--- a/backup.nix
+++ b/backup.nix
@@ -17,7 +17,7 @@ let
     tar -cz -C /var/lib/redis-misskey .
   '';
 
-  notifyError = pkgs.writeShellApplication {
+  notifyErrorPkg = pkgs.writeShellApplication {
     name = "notify-error";
 
     runtimeInputs = [ pkgs.system-sendmail ];
@@ -111,7 +111,7 @@ in {
       invocationId="$(systemctl show --value -p InvocationID misskey-backup.service)"
       logs="$(journalctl _SYSTEMD_INVOCATION_ID= -u misskey-backup.service)"
 
-      ${notifyError} "backup" "Misskey Backup Failure Notification" "$(<<EOMSG
+      ${notifyErrorPkg}/bin/notify-error "backup" "Misskey Backup Failure Notification" "$(<<EOMSG
       A backup process has failed. Logs to follow:
 
       $logs