DataGridViewComboBoxCell Binding - "value is not valid"

I'm trying to bind separate ComboBox cells within a DataGridView to a custom class, and keep getting an error

DataGridViewComboBoxCell value is not valid

I'm currently assigning the data source for the cell to an IList<ICustomInterface> from a Dictionary I've got. Upon setting the data source however, the index for the ComboBoxCell isn't set, so it has an invalid value selected.

I'm trying to figure out how to get it to select a real value, e.g. the 0th item within the list it has been given to remove this error, or find another way to solve the problem. Anyone have any suggestions?

Here's a complete example with a basic form and DataGridView added via the designer:

Setup and bindings:

private void Form1_Load(object sender, EventArgs e)
{

    var colors = new List<Code>()
    {
        new Code() {Value= "R", Text = "Red"},
        new Code() {Value= "G", Text = "Green"},
        new Code() {Value= "B", Text = "Blue"}
    };

    var users = new List<User>()
    {
        new User() {Name = "Briana", FavoriteColor = "B"},
        new User() {Name = "Grace", FavoriteColor = "G"}
    };

    var colorCol = new DataGridViewComboBoxColumn();
    colorCol.DataSource = colors;
    colorCol.DisplayMember = "Text";
    colorCol.ValueMember = "Value";
    colorCol.DataPropertyName = "FavoriteColor";

    dataGridView1.Columns.Add(colorCol);
    dataGridView1.DataSource = users;

}

Some classes:

public class Code
{
    public string Value { get; set; }
    public string Text { get; set; }
}

public class User
{
    public string Name { get; set; }
    public string FavoriteColor { get; set; }
}