Can not serialize interface message for Web service
In my asmx file, I have 

            [WebMethod]
            [ScriptMethod]
            public void Method(IDictionary<string, CustomClass> objectOfCustomClass)
            {
               //do stuff
            }

custom class is defined as:

    public class CustomClass
        {
            public string Prop1 { get; set; }
            public string Prop2 { get; set; }       
        }


All goes well and the web service is being successfully consumed from Jquery ajax method. Recently I decided to test and try and access it from the direct URL such as http://localhost/Services.asmx/Method

and I get this message

"Cannot serialize interface System.Collections.Generic.IDictionary"

This seems off. What's causing it and is it normal? 
Can not serialize interface message for Web service
===

In my asmx file, I have 

            [WebMethod]
            [ScriptMethod]
            public void Method(IDictionary<string, CustomClass> objectOfCustomClass)
            {
               //do stuff
            }

custom class is defined as:

    public class CustomClass
        {
            public string Prop1 { get; set; }
            public string Prop2 { get; set; }       
        }


All goes well and the web service is being successfully consumed from Jquery ajax method. Recently I decided to test and try and access it from the direct URL such as http://localhost/Services.asmx/Method

and I get this message

"Cannot serialize interface System.Collections.Generic.IDictionary"

This seems off. What's causing it and is it normal? 