diff --git a/things/calculator/http/flask/main.py b/things/calculator/http/flask/main.py
index eac0e01..21d5f06 100644
--- a/things/calculator/http/flask/main.py
+++ b/things/calculator/http/flask/main.py
@@ -22,11 +22,11 @@
 
 cli.show_server_banner = lambda *x: click.echo("ThingIsReady")
 
-hostname = "0.0.0.0"
+td_hostname = "0.0.0.0"
 portNumber = 5000
 
 if "HOSTNAME" in os.environ:
-    hostname = os.environ["HOSTNAME"]
+    td_hostname = os.environ["HOSTNAME"]
 
 if "PORT" in os.environ:
     portNumber = os.environ["PORT"]
@@ -44,7 +44,7 @@
 thingModel["@type"] = 'Thing'
 thingModel = json.dumps(thingModel)
 thingModel = thingModel.replace('{{PROTOCOL}}', 'http')
-thingModel = thingModel.replace('{{HOSTNAME}}', hostname)
+thingModel = thingModel.replace('{{HOSTNAME}}', td_hostname)
 thingModel = thingModel.replace('{{PROPERTIES}}', PROPERTIES)
 thingModel = thingModel.replace('{{ACTIONS}}', ACTIONS)
 thingModel = thingModel.replace('{{EVENTS}}', EVENTS)
@@ -158,4 +158,4 @@ def stream():
     port = 5000
 
 if __name__ == "__main__":
-    app.run(debug=False, host=hostname, port=port)
+    app.run(debug=False, host="0.0.0.0", port=port)