Docker-composeで構築したWebサーバーにアクセスすると503エラーが発生する

前提・実現したいこと

現在、ConohaVPSにて、Dockerを利用したWebサーバーを構築したいと考えております。
OSはCentOS7を利用しており、nginxとWordpressで環境を構築しようと考えています。
そこで、Docker-composeにて定義を記載しているのですが、以下の問題が発生し、うまくいきません。

発生している問題・エラーメッセージ

アクセス時のエラー
503 Service Temporarily Unavailable
nginx/1.14.1

ConsoleError
1docker-compose up
2Starting mysql         ... done
3Recreating nginx_proxy ... done
4Recreating wp_1                                    ... done
5Recreating web_letsencrypt-nginx-proxy-companion_1 ... done
6Attaching to mysql, nginx_proxy, wp_1, web_letsencrypt-nginx-proxy-companion_1
7mysql                                | 2019-02-11T07:49:36.459102Z 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).
8mysql                                | 2019-02-11T07:49:36.461474Z 0 [Note] mysqld (mysqld 5.7.21) starting as process 1 ...
9mysql                                | 2019-02-11T07:49:36.465343Z 0 [Note] InnoDB: PUNCH HOLE support available
10・・・文字数制限により省略
11'/var/run/mysqld/mysqld.sock'  port: 3306  MySQL Community Server (GPL)
12nginx_proxy                          | Custom dhparam.pem file found, generation skipped
13nginx_proxy                          | forego     | starting dockergen.1 on port 5000
14nginx_proxy                          | forego     | starting nginx.1 on port 5100
15nginx_proxy                          | dockergen.1 | 2019/02/11 07:49:36 Error inspecting container: ea19cff1bc5be4c6301bff54547f806757a6d5f30472f6b457b8e244a273a9e9: No such container: ea19cff1bc5be4c6301bff54547f806757a6d5f30472f6b457b8e244a273a9e9
16nginx_proxy                          | dockergen.1 | 2019/02/11 07:49:36 Watching docker events
17nginx_proxy                          | dockergen.1 | 2019/02/11 07:49:36 Contents of /etc/nginx/conf.d/default.conf did not change. Skipping notification 'nginx -s reload'
18nginx_proxy                          | dockergen.1 | 2019/02/11 07:49:37 Received event start for container c8e9c7699f4f
19nginx_proxy                          | dockergen.1 | 2019/02/11 07:49:37 Error inspecting container: b726244313d5cc241d6332f128b56ca685498e73ede891255dd237304d9c0c58: No such container: b726244313d5cc241d6332f128b56ca685498e73ede891255dd237304d9c0c58
20nginx_proxy                          | dockergen.1 | 2019/02/11 07:49:37 Contents of /etc/nginx/conf.d/default.conf did not change. Skipping notification 'nginx -s reload'
21nginx_proxy                          | dockergen.1 | 2019/02/11 07:49:37 Error inspecting container: f5dd87efde0168b0625df63d473177cfcc35e2f42ccb9d097a72a7238dce8cd2: No such container: f5dd87efde0168b0625df63d473177cfcc35e2f42ccb9d097a72a7238dce8cd2
22nginx_proxy                          | dockergen.1 | 2019/02/11 07:49:37 Contents of /etc/nginx/conf.d/default.conf did not change. Skipping notification 'nginx -s reload'
23wp_1                                 | AH00558: apache2: Could not reliably determine the server's fully qualified domain name, using 172.21.0.4. Set the 'ServerName' directive globally to suppress this message
24wp_1                                 | AH00558: apache2: Could not reliably determine the server's fully qualified domain name, using 172.21.0.4. Set the 'ServerName' directive globally to suppress this message
25wp_1                                 | [Mon Feb 11 07:49:37.489356 2019] [mpm_prefork:notice] [pid 1] AH00163: Apache/2.4.25 (Debian) PHP/7.2.15 configured -- resuming normal operations
26wp_1                                 | [Mon Feb 11 07:49:37.489441 2019] [core:notice] [pid 1] AH00094: Command line: 'apache2 -D FOREGROUND'
27letsencrypt-nginx-proxy-companion_1  | Info: Custom Diffie-Hellman group found, generation skipped.
28letsencrypt-nginx-proxy-companion_1  | Reloading nginx proxy (cf928d77d9d7e8a12e85d0c8a0a187d11c23364d659af7a90d38069e78f361e6)...
29letsencrypt-nginx-proxy-companion_1  | 2019/02/11 07:49:38 Contents of /etc/nginx/conf.d/default.conf did not change. Skipping notification ''
30letsencrypt-nginx-proxy-companion_1  | 2019/02/11 07:49:38 [notice] 61#61: signal process started
31letsencrypt-nginx-proxy-companion_1  | 2019/02/11 07:49:38 Generated '/app/letsencrypt_service_data' from 4 containers
32letsencrypt-nginx-proxy-companion_1  | 2019/02/11 07:49:38 Running '/app/signal_le_service'
33letsencrypt-nginx-proxy-companion_1  | 2019/02/11 07:49:38 Watching docker events
34letsencrypt-nginx-proxy-companion_1  | 2019/02/11 07:49:38 Contents of /app/letsencrypt_service_data did not change. Skipping notification '/app/signal_le_service'
35letsencrypt-nginx-proxy-companion_1  | /etc/nginx/certs/<ドメイン> /app
36letsencrypt-nginx-proxy-companion_1  | Reloading nginx proxy (cf928d77d9d7e8a12e85d0c8a0a187d11c23364d659af7a90d38069e78f361e6)...
37letsencrypt-nginx-proxy-companion_1  | 2019/02/11 07:49:38 Contents of /etc/nginx/conf.d/default.conf did not change. Skipping notification ''
38letsencrypt-nginx-proxy-companion_1  | 2019/02/11 07:49:38 [notice] 86#86: signal process started
39letsencrypt-nginx-proxy-companion_1  | Creating/renewal <ドメイン> certificates... (<ドメイン>)
40letsencrypt-nginx-proxy-companion_1  | 2019-02-11 07:49:40,612:INFO:simp_le:1479: Generating new certificate private key
41letsencrypt-nginx-proxy-companion_1  | 2019-02-11 07:49:43,148:ERROR:simp_le:1446: CA marked some of the authorizations as invalid, which likely means it could not access http://example.com/.well-known/acme-challenge/X. Did you set correct path in -d example.com:path or --default_root? Are all your domains accessible from the internet? Please check your domains' DNS entries, your host's network/firewall setup and your webserver config. If a domain's DNS entry has both A and AAAA fields set up, some CAs such as Let's Encrypt will perform the challenge validation over IPv6. If your DNS provider does not answer correctly to CAA records request, Let's Encrypt won't issue a certificate for your domain (see https://letsencrypt.org/docs/caa/). Failing authorizations: https://acme-v01.api.letsencrypt.org/acme/authz/EaMASnYu7L-fNkwVZnCVeyZftyxJUDtQML1RShpgSDA
42letsencrypt-nginx-proxy-companion_1  | Challenge validation has failed, see error log.
43letsencrypt-nginx-proxy-companion_1  |
44letsencrypt-nginx-proxy-companion_1  | Debugging tips: -v improves output verbosity. Help is available under --help.
45letsencrypt-nginx-proxy-companion_1  | /app
46letsencrypt-nginx-proxy-companion_1  | Sleep for 3600s

Docker-composeにて記載している内容が以下になります。

Docker-compose.yml

version: '2'
services:
  db:
    container_name: mysql
    image: mysql:5.7.21
    ports:
      - 3306:3306
    volumes:
      - /home/web/mysql:/var/lib/mysql
    environment:
      MYSQL_ROOT_PASSWORD: password
    restart: always
    networks:
      - net-proxy

  wordpress1:
    container_name: wp_1
    depends_on:
      - db
    image: wordpress
    volumes:
      - /home/web/wordpress/wp_1/wp-content:/var/www/html/wp-content
    external_links:
     - db
    expose:
      - 80

    environment:
      # VIRTUAL_HOST: <ドメイン> #WordPresドメイン名
      WORDPRESS_DB_HOST: db:3306
      WORDPRESS_DB_PASSWORD: password
      LETSENCRYPT_HOST: <ドメイン>
      LETSENCRYPT_EMAIL: ebonight02@gmail.com # Lets Encrypt
    restart: always
    networks:
      - net-proxy

  letsencrypt-nginx-proxy-companion:
    image: jrcs/letsencrypt-nginx-proxy-companion
    volumes:
      - /home/web/certs:/etc/nginx/certs:rw
      - /var/run/docker.sock:/var/run/docker.sock:ro
    volumes_from:
      - nginx-proxy
    restart: always
    networks:
      - net-proxy

  nginx-proxy:
    container_name: nginx_proxy
    image: jwilder/nginx-proxy
    privileged: true
    ports:
      - 80:80
      - 443:443
    volumes:
      - /etc/nginx/vhost.d
      - /usr/share/nginx/html
      - /var/run/docker.sock:/tmp/docker.sock:ro
      - /home/home/web/certs:/etc/nginx/certs:ro
    restart: always
    networks:
      - net-proxy
    environment:
      DEFAULT_HOST: <ドメイン>

networks:
  net-proxy:
    external: true

正直どこがだめなのか全くわからない状態です。
VPS側のAレコード等は設定済みとなります。
もし何か分かる方いましたらご教示お願いいたします。