Add Connection to SQL Server 2014 Fails?

Hope this is the right Forum for this question.

I managed to "Connect" to a network SQL Server 2014 Express. In my .NET application, when I try to "Add connection" to the database, I get to this point (which takes forever?):

At this point, in the Connect to database section, in the database list box, every database on the selected Server should appear. But when I try to access the list, I get greeted by this error message :

I can see very briefly the "name" of the databases in the list but it is immediately followed by the error message.

I'll have to research "SSPI" and the "target principal name"? 

Any help is appreciated.