Hi Bal,

I ran this on a fresh Umbraco installation and immediately ran into the following error:

Unable to load form: The type initializer for 'Nested' threw an exception.

So, I played around and looks like there's something wrong with your GUID. I swapped this out for a newly generated GUID and it seems to work just fine (error is no longer displaying, but I haven't tested the whole form workflow, I'll leave that to you).

Here's a tweaked version of your code:

using System;
using System.Collections.Generic;
using System.Web;
using Umbraco.Forms.Core;
using Umbraco.Forms.Core.Enums;

namespace UmbracoSandbox.WorkflowTypes
{
    public class MissedBinEmailWorkflow : WorkflowType
    {
        public MissedBinEmailWorkflow()
        {
            Id = new Guid("7793f98d-266f-4905-b2f2-9d27438da763");
            Name = "A Missed Bin Email";
            Description = "Send Email to Cutomer ";
        }

        public override WorkflowExecutionStatus Execute(Record record, RecordEventArgs e)
        {
            foreach (var field in record.RecordFields.Values)
            {
                List<object> fieldItem = field.Values;
                string fieldName = field.Field.Caption;

                if (fieldName == "Is there a yellow or red tag on your bin")
                {
                    List<object> fieldValue = fieldItem;

                    foreach (string fv in fieldValue)
                    {
                        if (fv == "Yes")
                        {
                            HttpContext.Current.Response.Redirect("https://www.google.com");
                        }
                    }
                }
            }

            return WorkflowExecutionStatus.Completed;
        }

        public override List<Exception> ValidateSettings()
        {
            return new List<Exception>();
        }
    }
}

Hope that helps!