Ismail,
You need to change that password QUICK! and edit your post to remove that info!
You have security enabled on your ArcGIS Server using Windows authentication so access to your map services using the external server name requires a login or you need to generate a token to be used by the service and add that token to the ArcGISDynamicMapServiceLayer. I attempted to generate a token for testing using the credentials you gave but your server is not configured correctly for external access to generate tokens.