Connecting to a SQL Server Named Instance, from remote client, outside network

Hi All,

I have what I feel may be a newbie question.

I am trying to connect Visual Studio SQL Server Object Explorer to a named instance of SQL server. The instance is sitting on a VM in Azure, and there is a port endpoint set up. The external port X is mapped to 1433 on the VM hosting SQL.

I am getting this error when I try to connect in the following ways webname\instance,port webname,port\instance webname,port

The Azure server name is : serviceName.cloudapp.net
The Instance is: INSTANCE
And the port is the external port number: 1234

I feel like I am making the newbie mistake in how I am naming the connection info. I have a valid set of SQL credentials that I have check locally. They cannot connect when outside the network, through the port.