My problem was in my connection to the database I solved my error creating a VB class in the APP_Code folder and everytime I need to access my connection string I call a funtion that returns a string with my connection.
Dim link As String = "connection string"
Public funtion something()
return link
end function

and every time i need the connection I do this

Dim css As New DataAccess()
Dim teste As String = css.Link()

Using con As New System.Data.SqlClient.SqlConnection(teste)
con.Open()

I really don´t know if it was a good solution but at least it´s working now.