Below is my connection string:
connectionString=\"metadata=res://*/EDMX.Test.csdl|res://*/EDMX.Test.ssdl|res://*/EDMX.Test.msl;provider=System.Data.Sq
I faced the same issue. Though in my case I was trying to connect my desktop application to a remote db. So for me, all the above didn't work. I solve this problem by just adding the port (as 128.02.39.29:3315) and it magically works!
The reason why I didn't bother to add the port in the first place is because I used same approach (without the port) in another desktop app and it worked.
So I hope this might help someone as well.