anti-forgery cookie exception with sitecore wfffm form

I am getting the below error message. We thought it could be because of multiple CD servers so did used same machine key. But we are still getting this error. Not sure what is causing the problem.

 

 

ERROR The required anti-forgery cookie "__RequestVerificationToken" is not present. Exception: System.Web.Mvc.HttpAntiForgeryException Message: The required anti-forgery cookie "__RequestVerificationToken" is not present. Source: System.Web.WebPages at System.Web.Helpers.AntiXsrf.TokenValidator.ValidateTokens(HttpContextBase httpContext, IIdentity identity, AntiForgeryToken sessionToken, AntiForgeryToken fieldToken) at System.Web.Helpers.AntiXsrf.AntiForgeryWorker.Validate(HttpContextBase httpContext, String cookieToken, String formToken) at Sitecore.Forms.Mvc.Controllers.Filters.WffmValidateAntiForgeryTokenAttribute.OnAuthorization(AuthorizationContext filterContext) at System.Web.Mvc.ControllerActionInvoker.InvokeAuthorizationFilters(ControllerContext controllerContext, IList`1 filters, ActionDescriptor actionDescriptor) at System.Web.Mvc.ControllerActionInvoker.InvokeAction(ControllerContext controllerContext, String actionName)