「504 Gateway Time-out」の解決方法及びコードチェックのお願い

504 Gateway Time-out

【confing/routes.rb】

Rails.application.routes.draw do
  root to: 'toppages#index'

  get 'login', to: 'sessions#new'
  post 'login', to: 'sessions#create'
  delete 'logout', to: 'sessions#destroy'

  get 'signup', to: 'users#new'
  resources :users, only: [:index, :show, :new, :create] do
    member do
      get :followings
      get :followers
    end
  end

  resources :microposts, only: [:create, :destroy]
  resources :relationships, only: [:create, :destroy]
  resources :favorites, only:[:create, :destroy]
end

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【views/_favorite_button.html.erb】


  <% if current_user.favorite?(micropost) %>
    <%= form_with(model: current_user.favorites.find_by(:micropost_id), local: true, method: :delete) do |f| %>
      <%= hidden_field_tag :micropost_id %>
      <%= f.submit 'Unfavorite', class: 'btn btn-danger btn-block' %>
    <% end %>
  <% else %>
    <%= form_with(model: current_user.favorites.build, local: true) do |f| %>
      <%= hidden_field_tag :micropost_id %>
      <%= f.submit 'Favorite', class: 'btn btn-primary btn-block' %>
    <% end %>
  <% end %>


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【controllers/favorites_controller.rb】
class FavoritesController < ApplicationController

  before_action :require_user_logged_in

  def create
    micropost = Micropost.find(params[:micropost_id])
    current_user.favorite(micropost)
    flash[:success] = 'お気に入りしました。'
    redirect_to micropost
  end

  def destroy
    micropost = Micropost.find(params[:micropost_id])
    current_user.unfavorite(user)
    flash[:success] = 'お気に入りを解除しました。'
    redirect_to micropost
  end
end


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【models/user.rb】
class User < ApplicationRecord
  before_save { self.email.downcase! }
  validates :name, presence: true, length: { maximum: 50 }
  validates :email, presence: true, length: { maximum: 255 },
                    format: { with: /\A[\w+\-.]+@[a-z\d\-.]+\.[a-z]+\z/i },
                    uniqueness: { case_sensitive: false }
  has_secure_password

  has_many :microposts
  has_many :relationships
  has_many :followings, through: :relationships, source: :follow
  has_many :reverses_of_relationship, class_name: 'Relationship', foreign_key: 'follow_id'
  has_many :followers, through: :reverses_of_relationship, source: :user
  has_many :favorites
  has_many :favorites, through: :favorites, source: :micropost
  has_many :reverses_of_favorite, class_name: 'Favorite', foreign_key: 'micropost_id'

  def follow(other_user)
    unless self == other_user
      self.relationships.find_or_create_by(follow_id: other_user.id)
    end
  end

  def unfollow(other_user)
    relationship = self.relationships.find_by(follow_id: other_user.id)
    relationship.destroy if relationship
  end

  def following?(other_user)
    self.followings.include?(other_user)
  end

  def feed_microposts
    Micropost.where(user_id: self.following_ids + [self.id])
  end


  def like
  unless self == other_micropost
      self.favorites.find_or_create_by(micropost_id: other_user.id)
  end
  end

  def unlike
    favorite = self.favorite.find_by(micropost_id: other_user.id)
    favorite.destroy if favorite
  end

  def favorite?(other_user)
    self.microposts.include?(other_user)
  end



end

### 自分で試したこと
lsof -i :8080→kill -9　PID番号　と入力後、再起動を試しましたが変わらずでした、、
ご教授いただけますと幸いです。
よろしくお願いいたします。