My actionContext is null when called in using Swagger

I have ASP.net application that uses model validation using OnActionExecuting method.

public override void OnActionExecuting(HttpActionContext actionContext)
        {
            if (!actionContext.ModelState.IsValid)
            {
                actionContext.Response = actionContext.Request.CreateResponse(HttpStatusCode.BadRequest, GetModelStateErrorMessages(actionContext));
            }
        }

My problem here is that always actionContext values are null. I am calling the API using swagger. enter image description here

My controller section is as follows :

[AllowAnonymous]
    [HttpGet]
    [ValidateModelState,CheckModelForNull]
    [Route("api/foodordersystem/SendEmailToCustomer/[EmailAddress]")]
    public string SendEmailToCustomerAPI(GeneralData emailAddress)
    {
        CreateDataConnection();
        string stat = "";

Swagger screen : enter image description here

Any help is greatly appreciated.

Thank you. PG