Hi to everyone. I'm having difficult obtaining the ErrorMesage from my class in a Surface Controller Form. Everything works as expected except for the validation message when a required checkbox must be ticked. I've been trying many things, but the result is always the same: No Error Message.

Following is part of my Model:

        [Required(ErrorMessage = "L'Oggetto della richiesta è un campo Obbligatorio")]
    [Display(Name = "Oggetto")]
    public string Oggetto { get; set; }

    [Required(ErrorMessage = "La Descrizione della richiesta è un campo Obbligatorio")]
    [Display(Name = "Descrizione")]
    public string Descrizione { get; set; }

    //[Required(ErrorMessage = "È necessario confermare di aver letto l'informativa sulla privacy.")]
    //[Range(typeof(bool), "false", "true", ErrorMessage = "È necessario confermare di aver letto")]    // funziona a rovescio
    [Range(typeof(bool), "true", "true", ErrorMessage = "È necessario confermare di aver letto l'informativa!")]
    [Display(Name = "Informativa sulla Privacy")]
    public bool Privacy { get; set; }

As you can see I have tried also with the [Required] attribute.

Following is the View fragment:

    @* Privacy *@
    <div class="row mb-3">
        <div class="col">
            @Html.CheckBoxFor(m => m.Privacy, new { @class = "form-check form-check-inline", @style = "width:25px; height:25px" })
            @Html.LabelFor(m => m.Privacy)<i>&ast;</i>
            @Html.ValidationMessageFor(m => m.Privacy, "", new { @class = "text-danger font-weight-bold blinkingText" })
        </div>
    </div>

    @* Submit *@
    <div class="row mb-3">
        <div class="col text-center">
            <input type="submit" value="Invia Richiesta" class="btn btn-cyan" />
        </div>
    </div>

the view fragment is wrapped inside a using (Html.BeginUmbracoForm("Submit", "FormContatti"))

When I submit with missing fields I get back to the view with all error messages displayed except for the checkbox that has to by ticked:

Anyone can help? Thanks René