app/setup/setups/logs.php

@@ -91,7 +91,7 @@ return [
                 $params += $handlerData['levels'];
             } else {
                 $params []= $handlerData['levels'];
-                $params []= null;
+                $params []= Monolog\Level::Emergency;
             }
             $params []= false;
             $handlers []= new Monolog\Handler\FilterHandler(...$params);