I got this Error: resource not found for the segment 'emailSet'

My Code is:

function createREST()
{
    var createEmail= {};
createEmail.RegardingObjectId= { id: "CA6A23C2-14A8-47EF-BAA8-8AA05AEFFDFA" , logicalName: "email", type: "EntityReference" };

    SDK.REST.createRecord(
         createEmail,
         "email",
         function (createEmail) {
         },
         function errorHandler(error)
         {
             alert(error.message);
         }
       );
}