I've made a custom field called TFS Incident for our Support Tickets. I am trying to use the Zoho API to try and search for Zoho tickets with a particular TFS Incident, but it keeps coming back saying there are no results even though I know that there are Zoho Tickets with this particular TFS Incident since I created them myself. Here is a sample url:

https://support.zoho.com/api/json/requests/getrecordsbysearch?authtoken=token&portal=ourcompany&department=ourdepartment&searchfield=TFS Incident&searchvalue=12345

Am I using the wrong module for searching support tickets, or can the API not search for custom fields? Or is there something else wrong that I'm not seeing?