Knowledge Advance Search API giving empty result

Summary:

In knowledge Advance search API it is giving empty result as below .

API : https://sitename-irs.custhelp.com/srt/api/latest/search/question?question=mobile

Header:

kmauthtoken: {"siteName":"sitename","interfaceId":"1","integrationUserToken":"dnpfemVhcmNoX190c3QxOnhNWThBMkY2ZUZPd1MvZVo1K1B4TmNDMjY5OEo3VG9QNFlEcU4yU3FrSURJck1ZZVdVVDNQZ3E3KzNSMVRwZlozYlFrbTlaRzF4S25wRzArVzlESGk5R3BYZENxeExwanVPN1BVWHhUU1Roak1TLzlJMzFPS1hGZW9DYm5Ed01hK3JIU3g1QzE1UzVmTWd1d08yQVJOYktlM1RzNjJ0MThvZnEvVFNYSmJOST0="}

Accept: application/json

Content-Type: application/json

Body:

{

  "session" : "242204f72c9331-2dc0-48d7-a50f-f19b49c8d58d",

  "transactionId" : 879067398,

  "facetPriorTransactionId" :0

}

Response:

{

    "results": {

        "results": [],

        "facets": []

    },

    "query": {

        "interactive": false,

        "original": "mobile",

        "paraphrase": "mobile"

    },

    "session": "242204a8efea85-c910-4258-8a12-2f2c70772083",