Incident creation using REST API - mailbox issue

Content

Hi All,

I am creating an incident using Rest api in right now  . When  my incident gets created the mail box value is null. But i have set [email protected] as my default mailbox in right now. So whenever i create a incident manually it gets assigned to default mailbox.

please find by request body below:

Now whether i want to add mailbox details also to request body while creating an incident.

Version

Service cloud

Code Snippet

             {
   "primaryContact": {
      "id":1492
	},
	
   "subject": "JSON test",
 
   "customFields": {
	 "c": {
      "reservation_num": "123",
      "lang": "English"
	}
   },   
  
   "category": {
	   "lookupName": "Fares"
    },
  
   "threads": {
     "contentType": {
       "lookupName": "text/plain"
      },