diff --git a/modules/timers/backup.nix b/modules/timers/backup.nix
index 9c6aa75..8db477a 100644
--- a/modules/timers/backup.nix
+++ b/modules/timers/backup.nix
@@ -20,7 +20,7 @@ in {
     systemd.timers."backupSyncthing" = {
       wantedBy = ["timers.target"];
       timerConfig = {
-        onCalendar = "weekly";
+        OnCalendar = "weekly";
         Persistent = true;
       };
     };