Task/Create not creating a task

I am using the task create rest api.The issue is that the task is not getting created. I am using version 8.0

This is the code-

var request = new CTask()
{
name = “Moderator Approval”,
processInstanceId = “dca7e53f-596e-11ef-b926-000d3af072d2”,
assignee = “Mary”,
description = “test”,
executionId= “dca7e53f-596e-11ef-b926-000d3af072d2”,
processDefinitionId= “d93ca08a-4348-11ef-b926-000d3af072d2”
};

        var taskQueryResult = await HttpPost("task/create", request);

Please advise.