Failed to create ticket with status [Solved]

Hi team, I am trying to create the new ticket with status [Solved] for some business purpose, but even I set the assignee before I created the ticket, I still got the error:

{
    "error":"RecordInvalid",
    "description":"Record validation errors",
    "details":{
        "base":[
            {
                "description":"담당자: 티켓을 해결할 때 필요합니다.",
                "error":null,
                "ticket_field_id":360012873314,
                "ticket_field_type":"FieldAssignee"
            }
        ]
    }
}

and the rest api I called is: 

/tickets.json

So would you please check this issue, it has been blocked for days. thanks!