rails strong parameters not work correctly

i have a rails app. i have strange problem in saving form

this is my ticket model .

class Ticket < ApplicationRecord
  belongs_to :user
  has_many :ticketissues , inverse_of: :ticket

  accepts_nested_attributes_for :ticketissues, :reject_if => lambda { |a| a[:body].blank? }

end

this is ticketisue model

    class Ticketissue < ApplicationRecord

      belongs_to :user
      belongs_to :ticket

     validates :body, presence: true
    end

this is ticket controller

class TicketsController < ApplicationController
  before_action :set_ticket, only: [:show, :edit, :update, :destroy]

  # GET /tickets
  # GET /tickets.json
  def index
    @tickets = Ticket.all
  end

  # GET /tickets/1
  # GET /tickets/1.json
  def show
  end

  # GET /tickets/new
  def new
    @ticket = Ticket.new
  end

  # GET /tickets/1/edit
  def edit
  end

  # POST /tickets
  # POST /tickets.json
  def create
    @ticket = Ticket.new(ticket_params)
    @ticket.user_id = current_user.id
    @ticket.ticketissues.build

    respond_to do |format|
      if @ticket.save
        format.html { redirect_to @ticket, notice: 'Ticket was successfully created.' }
        format.json { render :show, status: :created, location: @ticket }
      else
        format.html { render :new }
        format.json { render json: @ticket.errors, status: :unprocessable_entity }
      end
    end
  end

  # PATCH/PUT /tickets/1
  # PATCH/PUT /tickets/1.json
  def update
    respond_to do |format|
      if @ticket.update(ticket_params)
        format.html { redirect_to @ticket, notice: 'Ticket was successfully updated.' }
        format.json { render :show, status: :ok, location: @ticket }
      else
        format.html { render :edit }
        format.json { render json: @ticket.errors, status: :unprocessable_entity }
      end
    end
  end

  # DELETE /tickets/1
  # DELETE /tickets/1.json
  def destroy
    @ticket.destroy
    respond_to do |format|
      format.html { redirect_to tickets_url, notice: 'Ticket was successfully destroyed.' }
      format.json { head :no_content }
    end
  end

  private
    # Use callbacks to share common setup or constraints between actions.
    def set_ticket
      @ticket = Ticket.find(params[:id])
    end

    # Never trust parameters from the scary internet, only allow the white list through.
    def ticket_params
      params.require(:ticket).permit(:subject, :subsubject, :user_id, ticketissues_attributes: [ 
        :body, :id, :_destroy] )
      #params.require(:ticket).permit!
    end
end

and my view is like this

<%= f.input :subject , collection: [ "تغییر اطلاعات کسب و کار",
                                     "تغییر اطلاعات یک کوپن",
                                     "سایر موارد"] %>

    <%= f.input :subsubject %>
   <!-- <%= f.association :user %> -->
  </div>

      <%= f.simple_fields_for :ticketissue do |p| %>
        <%= p.input :body  %>
      <% end %>

  <div class="form-actions">
    <%= f.button :submit %>
  </div>
<% end %>

but when i want to create a ticket , form will not save to database and i get this error:

Started POST "/tickets" for 127.0.0.1 at 2017-04-11 23:52:33 +0430

Processing by TicketsController#create as HTML
  Parameters: {"utf8"=>"✓", "authenticity_token"=>"fsl6nTe0PjmBKpeuh16BRFlYOw0MB93LEYDVEAl6TtT/uu/LwGTA0P2q0bRxIxBUqHqZINXHntrZLt7MuCG84Q==", "ticket"=>{"subject"=>"تغییر اطلاعات کسب و کار", "subsubject"=>"lk", "ticketissue"=>{"body"=>"lkjkjkjkjkkjkj"}}, "commit"=>"Create Ticket"}
Unpermitted parameter: ticketissue

but when i use console and this command:

Ticket.create(subject: 'test' , subsubject: 'ticket test' , ticketissues_attributes: [{body: "[some thing" }] )

every things work fines and all data save.

tanks for read and help.