There is no consumer connection point 'IMessageConsumer' on 'bla [2]'.

I created a static connected webpart.
INTERFACE:
public interface IMessage
{
    string Message { get;}
}

USERCONTROL PROVIDER:
public partial class Control1 : System.Web.UI.UserControl, IMessage,
IWebPart
{
    protected void Page_Load(object sender, EventArgs e)
    {
    }
    [ConnectionProvider("Message","IMessageProvider")]
    public IMessage GetMessage()
    {
        return this;
    }
    public string Message
    {
        get
        {
            return TextBox1.Text;
        }
    }
    #region I ...