diff --git a/compose/watchtower/docker-compose.yml b/compose/watchtower/docker-compose.yml
index 3417798..816462b 100644
--- a/compose/watchtower/docker-compose.yml
+++ b/compose/watchtower/docker-compose.yml
@@ -9,7 +9,7 @@ services:
     environment:
       TZ: "${TZ:-Europe/Rome}"
       WATCHTOWER_CLEANUP: "${WATCHTOWER_CLEANUP:-false}"
-      WATCHTOWER_SCHEDULE: "${WATCHTOWER_SCHEDULE:?Schedule not set}"
+      WATCHTOWER_SCHEDULE: "${WATCHTOWER_SCHEDULE:?WATCHTOWER_SCHEDULE not set}"
       WATCHTOWER_SCOPE: "${WATCHTOWER_SCOPE:-}"
       WATCHTOWER_NOTIFICATION_URL: "${WATCHTOWER_NOTIFICATION_URL:-}"
     restart: always
\ No newline at end of file