Custom WCF REST Service Hosted in SharePoint 2013 - wcf

Question

I followed this wonderful post
SharePoint 2013: Create a Custom WCF REST Service Hosted in SharePoint
Now when I call a "GET" request everything work as expected. My problem with "POST" request, it always return 404 not found error response!
[OperationContract]
[WebInvoke( Method = "POST",
UriTemplate = "Approve",
RequestFormat = WebMessageFormat.Json,
ResponseFormat = WebMessageFormat.Json)]
bool Approve(PendingMeRequest pendingRequest);
Approve implementation is simple and return true
public bool Approve(PendingMeRequest pendingRequest)
{
return true;
//SPUser currentuser = SPContext.Current.Web.CurrentUser;
//return Take_approval_action(pendingRequest, "approve", currentuser.LoginName);
}
PendingMeRequest Model is simple with 3 string fields
public class PendingMeRequest
{
public string Key { set; get; }
public string RequestedBy { set; get; }
public string RequestTitle { set; get; }
}
When I call this method with jquery I get 404 not found error
$.ajax({
url: _spPageContextInfo.webAbsoluteUrl + '/_vti_bin/UnifiedWorklistService.svc/Approve/',
method: 'POST',
dataType: 'JSON',
data: JSON.stringify({pendingRequest: obj}),
contentType: 'application/json; charset=utf-8',
success: function (data) {
alert(data);
}
});
I tried to call it from POSTMAN but I got the same error
I think i miss something with Sharepoint configuration but I cannot figure it out
UPDATE:
After few hours of searching finally I found the problem, it is the trailing slash in the ajax call /_vti_bin/UnifiedWorklistService.svc/Approve/ should be removed!!
I cannot believe the time I wasted to figure it out...