The argument 'nameOrConnectionString' cannot be null, empty or contain only white space in Entity Framework project

I'm getting this error as soon as I try and initialize my DBContext Short background : I'm using a shared dll which contains DBcontext entity framework with all entites, this is referenced in my project along with enityframework.dll etc.

I can see all the classes within and here is the code in the Model.dll

namespace Model
{
    public class BSysDbContext : DbContext
    {
        public BSysDbContext(bool proxyCreationEnabled = true);

        public virtual DbSet<TaskResource> TaskResources { get; set; }
        public virtual DbSet<TaskOrder> TaskOrders { get; set; }
        public virtual DbSet<TaskMessage> TaskMessages { get; set; }
        public virtual DbSet<TaskEvent> TaskEvents { get; set; }
etc

In my code I'm trying to retrieve the data and it gets the above error when hitting this "_context = new BSysDbContext();"

    public partial class ChangeSupervisor : DevExpress.XtraEditors.XtraForm
    {


        BSysDbContext _context;
        public ChangeSupervisor()
        {
            InitializeComponent();
            _context = new BSysDbContext();

        }
    }

My connection string is :

  <connectionStrings>
    <add name="BSysDbContext" connectionString="metadata=res://Model.dll/BSysDbModel.csdl|
                                                         res://Model.dll/BSysDbModel.ssdl|
                                                         res://Model.dll/BSysDbModel.msl
                                                         ;provider=System.Data.SqlClient;provider connection string=';data source=DESKTOP-5T9EDLN;initial catalog=BuilderSysDB_DEV;user id=llduser;password=P@ssw0rd1;integrated security=True;MultipleActiveResultSets=True;App=EntityFramework';" providerName="System.Data.EntityClient" />
         </connectionStrings> 

No it doesn't matter what I put in the connection string, it doesn't seem to even know the string exists. According to what I've googled I don;t need to have the model.dll like this

public class BSysDbContext : DbContext
    {
      public BSysDbContext ()
            : base("name=BSysDbContext")
        {
        }
    }

Since the name is the same.

NB, I don't have access to the source of the DLL otherwise I would have made this change. All I need to know is... Is the missing "public BSysDbContext () : base("name=BSysDbContext") " in the DLL what is causing my error message or am I missing something here?

The connection string looks ok to me, I created another blank project and used that as a sample to create this one

Any advice is appreciated