試したこと

gmail 二段階認証を有効にした
安全性の低いアプリの許可を有効にした

コード

ruby
1Rails.application.routes.draw do
2  root "users#index"
3  resources :contacts
4  resources :users
5end

ruby
1class ContactsController < ApplicationController
2  def new
3  end
4
5  def create
6    @contact = Contact.new(contact_params)
7
8    if @contact.save
9      ContactMailer.contact_email(@contact).deliver_now
10      flash[:success] = '送信しました'
11      redirect_to(users_url)
12      # debugger
13    else
14      redirect_to(users_url)
15      flash[:success] = '失敗しました'
16    end
17  end
18
19  private
20
21  def contact_params
22    params.require(:contact).permit(:name, :message, :email)
23  end
24end

ruby
1class UsersController < ApplicationController
2  def index
3    @user = User.new
4    @contact = Contact.new
5  end
6
7  def create
8  end
9
10  def new
11  end
12
13  def edit
14  end
15end

erb
1<%= flash[:success] %>
2<header>
3  <p class="sub-title">fafadfa</p>
4  <h1 class="title">Let's play baseball</h1>
5  <p class="sub-title2">I can not find a prototype partner...</p>
6</header>
7
8<section class="link">
9
10</section>
11
12<section class="contact">
13  <h2>Contact</h2>
14  <%= form_for(@contact) do |f| %>
15    <%= f.label :Name, class: 'form-margin' %>
16    <%= f.text_field :name, class: 'form-control' %>
17    <%= f.label :Email, class: 'form-margin' %>
18    <%= f.text_field :email, class: 'form-control' %>
19    <%= f.label :Message, class: 'form-margin' %>
20    <%= f.text_field :message, class: 'form-control' %>
21    <%= f.submit 'SEND' %>
22  <% end %>
23</section>
24
25<footer class="footer">
26
27</footer>

ruby
1class ContactMailer < ApplicationMailer
2
3  def contact_email(contact)
4    @contact = contact
5    mail(
6      from: "#{@contact.name}",
7      to:   '任意のgmailアドレス',
8      subject: 'お問い合わせ通知'
9    )
10    # debugger
11  end
12end

ruby
1Rails.application.configure do
2  # Settings specified here will take precedence over those in config/application.rb.
3
4  # In the development environment your application's code is reloaded on
5  # every request. This slows down response time but is perfect for development
6  # since you don't have to restart the web server when you make code changes.
7  config.cache_classes = false
8
9  # Do not eager load code on boot.
10  config.eager_load = false
11
12  # Show full error reports.
13  config.consider_all_requests_local = true
14
15  # Enable/disable caching. By default caching is disabled.
16  # Run rails dev:cache to toggle caching.
17  if Rails.root.join('tmp', 'caching-dev.txt').exist?
18    config.action_controller.perform_caching = true
19
20    config.cache_store = :memory_store
21    config.public_file_server.headers = {
22      'Cache-Control' => "public, max-age=#{2.days.to_i}"
23    }
24  else
25    config.action_controller.perform_caching = false
26
27    config.cache_store = :null_store
28  end
29
30  # Store uploaded files on the local file system (see config/storage.yml for options)
31  config.active_storage.service = :local
32
33  # Don't care if the mailer can't send.
34  config.action_mailer.raise_delivery_errors = false
35
36  config.action_mailer.perform_caching = false
37
38  # Print deprecation notices to the Rails logger.
39  config.active_support.deprecation = :log
40
41  # Raise an error on page load if there are pending migrations.
42  config.active_record.migration_error = :page_load
43
44  # Highlight code that triggered database queries in logs.
45  config.active_record.verbose_query_logs = true
46
47  # Debug mode disables concatenation and preprocessing of assets.
48  # This option may cause significant delays in view rendering with a large
49  # number of complex assets.
50  config.assets.debug = true
51
52  # Suppress logger output for asset requests.
53  config.assets.quiet = true
54
55  # Raises error for missing translations
56  # config.action_view.raise_on_missing_translations = true
57
58  # Use an evented file watcher to asynchronously detect changes in source code,
59  # routes, locales, etc. This feature depends on the listen gem.
60  config.file_watcher = ActiveSupport::EventedFileUpdateChecker
61
62  # gmailの設定
63  config.action_mailer.delivery_method = :smtp
64  config.action_mailer.smtp_settings = {
65    address:              'smtp.gmail.com',
66    port:                  587,
67    domain:               'gmail.com',
68    user_name:            '任意のgmailアドレス',
69    password:             '付随するパスワード',
70    authentication:       'plain',
71    enable_starttls_auto:  true
72  }
73end

ログ

Started POST "/contacts" for ::1 at 2019-07-25 12:06:25 +0900
Processing by ContactsController#create as HTML
  Parameters: {"utf8"=>"✓", "authenticity_token"=>"3FdTVCpFBQdEijop3HzP6z63iyBZ2LBrlC1TOFmFQjFChKdUDT3jawbXPGoSYUzE8pz4JCAKqYp+pAyjUDmNvA==", "contact"=>{"name"=>"aaa", "email"=>"aaa@gmail.com", "message"=>"aaa"}, "commit"=>"SEND"}
   (0.1ms)  begin transaction
  ↳ app/controllers/contacts_controller.rb:8
  Contact Create (0.5ms)  INSERT INTO "contacts" ("name", "message", "created_at", "updated_at", "email") VALUES (?, ?, ?, ?, ?)  [["name", "aaa"], ["message", "aaa"], ["created_at", "2019-07-25 03:06:25.172183"], ["updated_at", "2019-07-25 03:06:25.172183"], ["email", "aaa@gmail.com"]]
  ↳ app/controllers/contacts_controller.rb:8
   (1.0ms)  commit transaction
  ↳ app/controllers/contacts_controller.rb:8
  Rendering contact_mailer/contact_email.html.erb within layouts/mailer
  Rendered contact_mailer/contact_email.html.erb within layouts/mailer (1.0ms)
  Rendering contact_mailer/contact_email.text.erb within layouts/mailer
  Rendered contact_mailer/contact_email.text.erb within layouts/mailer (0.7ms)
ContactMailer#contact_email: processed outbound mail in 41.7ms
Sent mail to 任意のアドレス (1588.4ms)
Date: Thu, 25 Jul 2019 12:06:25 +0900
From: aaa
To: 任意のアドレス
Message-ID: <5d391cb135a22_56923ff322bde23c355cc@r-kawata.local.mail>
Subject: =?UTF-8?Q?=E3=81=8A=E5=95=8F=E3=81=84=E5=90=88=E3=82=8F=E3=81=9B=E9=80=9A=E7=9F=A5?=
Mime-Version: 1.0
Content-Type: multipart/alternative;
 boundary="--==_mimepart_5d391cb1342e5_56923ff322bde23c354ed";
 charset=UTF-8
Content-Transfer-Encoding: 7bit


----==_mimepart_5d391cb1342e5_56923ff322bde23c354ed
Content-Type: text/plain;
 charset=UTF-8
Content-Transfer-Encoding: base64

YWFh5qeY44KI44KK44CB44GK5ZWP44GE5ZCI44KP44Gb44GM5bGK44GN44G+
44GX44Gf44CCDQotLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0t
LS0tLS0tLS0tLS0tLS0tLS0tLS0tDQoNCmFhYQ0KDQo=

----==_mimepart_5d391cb1342e5_56923ff322bde23c354ed
Content-Type: text/html;
 charset=UTF-8
Content-Transfer-Encoding: quoted-printable

<!DOCTYPE html>=0D
<html>=0D
  <head>=0D
    <meta http-equiv=3D"Content-Type" content=3D"text/html; charset=3Dutf=
-8" />=0D
    <style>=0D
      /* Email styles need to be inline */=0D
    </style>=0D
  </head>=0D
=0D
  <body>=0D
    <!DOCTYPE html>=0D
<html>=0D
  <head>=0D
    <meta content=3D'text/html; charset=3DUTF-8' http-equiv=3D'Content-Ty=
pe' />=0D
  </head>=0D
  <body>=0D
    <h1>aaa=E6=A7=98=E3=82=88=E3=82=8A=E3=80=81=E3=81=8A=E5=95=8F=E3=81=84=
=E5=90=88=E3=82=8F=E3=81=9B=E3=81=8C=E5=B1=8A=E3=81=8D=E3=81=BE=E3=81=97=E3=
=81=9F=E3=80=82</h1>=0D
      <p>=0D
      aaa=0D
    </p>=0D
  </body>=0D
</html>=0D
=0D
  </body>=0D
</html>=0D

----==_mimepart_5d391cb1342e5_56923ff322bde23c354ed--

Redirected to http://localhost:3000/users
Completed 302 Found in 1637ms (ActiveRecord: 1.6ms)


Started GET "/users" for ::1 at 2019-07-25 12:06:26 +0900
Processing by UsersController#index as HTML
  Rendering users/index.html.erb within layouts/application
  Rendered users/index.html.erb within layouts/application (2.4ms)
Completed 200 OK in 50ms (Views: 47.5ms | ActiveRecord: 0.0ms)

よろしくお願いいたします。