diff --git a/lib/tasks/mqtt_subscriber.rake b/lib/tasks/mqtt_subscriber.rake
index 68b4e271..df30a747 100644
--- a/lib/tasks/mqtt_subscriber.rake
+++ b/lib/tasks/mqtt_subscriber.rake
@@ -10,7 +10,7 @@ namespace :mqtt do
     mqtt_port = ENV.has_key?('MQTT_PORT') ? ENV['MQTT_PORT'] : 1883
     mqtt_ssl = ENV.has_key?('MQTT_SSL') ? ENV['MQTT_SSL'] : false
     mqtt_shared_subscription_group = ENV.fetch("MQTT_SHARED_SUBSCRIPTION_GROUP", nil)
-    mqtt_queue_length_warning_threshold = Env.fetch("MQTT_QUEUE_LENGTH_WARNING_THRESHOLD", 30)
+    mqtt_queue_length_warning_threshold = ENV.fetch("MQTT_QUEUE_LENGTH_WARNING_THRESHOLD", 30)
 
     mqtt_topics_string = ENV.fetch('MQTT_TOPICS', '')
     mqtt_topics = mqtt_topics_string.include?(",") ? mqtt_topics_string.split(",") : [ mqtt_topics_string ]