ActiveRecord::RecordNotFound in MessagesController#index

初学者の為、必要な情報が漏れている場合がございます。
漏れていた場合ご指摘いただけると幸いです。

前提・実現したいこと

エラー解除

発生している問題・エラーメッセージ

該当のソースコード

コントローラーの記載

class MessagesController < ApplicationController

  before_action :set_group

  def index
    @message = Message.new
    @messages = @group.messages.includes(:user)
  end

  def create
    @message = @group.messages.new(message_params)
    if @message.save
      redirect_to group_messages_path(@group), notice: 'メッセージが送信されました'
    else
      @messages = @group.messages.includes(:user)
      flash.now[:alert] = 'メッセージを入力してください。'
      render :index
    end
  end

  private

  def message_params
    params.require(:message).permit(:content, :image).merge(user_id: current_user.id)
  end

  def set_group
    @group = Group.find(params[:group_id])
    @groups = current_user.groups
  end
end

ルーティング

Rails.application.routes.draw do
  devise_for :users
  root 'messages#index'
  resources :users, only: [:edit, :update]
  resources :groups, only: [:new, :create, :edit, :update] do
    resources :messages, only: [:create, :index]
  end
end

rake routes

Prefix Verb                      URI Pattern                          Controller#Action
        new_user_session GET    /users/sign_in(.:format)             devise/sessions#new
            user_session POST   /users/sign_in(.:format)             devise/sessions#create
    destroy_user_session DELETE /users/sign_out(.:format)            devise/sessions#destroy
       new_user_password GET    /users/password/new(.:format)        devise/passwords#new
      edit_user_password GET    /users/password/edit(.:format)       devise/passwords#edit
           user_password PATCH  /users/password(.:format)            devise/passwords#update
                         PUT    /users/password(.:format)            devise/passwords#update
                         POST   /users/password(.:format)            devise/passwords#create
cancel_user_registration GET    /users/cancel(.:format)              devise/registrations#cancel
   new_user_registration GET    /users/sign_up(.:format)             devise/registrations#new
  edit_user_registration GET    /users/edit(.:format)                devise/registrations#edit
       user_registration PATCH  /users(.:format)                     devise/registrations#update
                         PUT    /users(.:format)                     devise/registrations#update
                         DELETE /users(.:format)                     devise/registrations#destroy
                         POST   /users(.:format)                     devise/registrations#create
                    root GET    /                                    messages#index
               edit_user GET    /users/:id/edit(.:format)            users#edit
                    user PATCH  /users/:id(.:format)                 users#update
                         PUT    /users/:id(.:format)                 users#update
          group_messages GET    /groups/:group_id/messages(.:format) messages#index
                         POST   /groups/:group_id/messages(.:format) messages#create
                  groups POST   /groups(.:format)                    groups#create
               new_group GET    /groups/new(.:format)                groups#new
              edit_group GET    /groups/:id/edit(.:format)           groups#edit
                   group PATCH  /groups/:id(.:format)                groups#update
                         PUT    /groups/:id(.:format)                groups#update