Problem in connection string by using ALWAYSON High Availability in SQL Server 2012

I am Using visual studio ultimate 2010 and SQL Server 2012 enterprise edition...

I have a database name as 'GBTest'

I just implemented ALWAYSON High Availability using 3 nodes in SQL Server 2012 latest feature...

among 3 nodes one as primary node and other two as secondary nodes. and 'Readable Secondary' option is 'No' on primary node and 'Yes' on two secondary node.

CLUSTER Name :- GBCLUSTER01

Availability Group Name:- GBTest_AvailGroup

and I am changing web config like this...

<add name="ConnectionString"
connectionString="Data Source=tcp:GBTest_AvailGroup,1433;Initial Catalog=GBTest;Integrated Security=SSPI" providerName="System.Data.SqlClient"/>

But its return a error...

I think there is some problem in my connection string ...Can anyone tell me the actual connection string??

Make sure that the listener is up and running

Open SSMS and see if you can connect to the listener. You should be able to

Your connection string format is correct in that you used the Availability Group listener name. However, what port number did you use to configure the listener? Is it 1433? Plus, check whether or not you have the Windows Firewall enabled. As SQL24 already mentioned, you should be able to use SSMS to validate connectivity to the Availability Group by using the listener name and the correct port number

Correct. You should be able to connect with Management Studio using the listener and Port.

The most likely cause of your Problem here is that in the properties of the listener you didn't specify a port number. You can easily check this in the SSMS UI.