Null connection string throws an exception error?

Question

Hi Team

 

I need some clarity on this exception errror, im getting an error stating connection string is null. Im using service-bus queue on Azure to send message on my portal. See below screen shot; What am missing exactly? My understanding is on AppConfig. first value should be my Queue-name(AddName is my current Queue-name), the value connectionString. Eg. Endpoint sb://mobilesmstwo.........) These are my connectionString from Azure portal.