さくらのVPS環境にて、WebSocket（Ratchet）のSSL通信が失敗する

前提・実現したいこと

Ratchet「PHPライブラリ」を使用し、「さくらのVPS」環境下に、WebSocketを実現しようとしております。
https://github.com/ginjake/php_chat
上記のサイトを参考にし、SSL化を行うまでは、js側のws接続にてWebSocket通信が正常に起動していることを確認いたしました。

SSL化を行った後、HTTPS環境下から、対象のWSサーバーへ通信した際に、

Failed to construct 'WebSocket': An insecure WebSocket connection may not be initiated from a page loaded over HTTPS.

というコンソールエラーが表示されたため、js側のwss接続方法へ変更いたしました。

wss接続へ変更した際に次は、

failed: Error in connection establishment: net::ERR_CONNECTION_REFUSED

js変更内容
×'ws://domain.xyz:8080/room/id/';
○'wss://domain.xyz:8080/room/id/';

Apacheの設定が正しく行えていないことが原因でしょうか？
サーバーやApacheについての知識不足のため、ご教示いただけますと幸いです。

js
1var requestUrl = 'wss://domain.xyz:8080/room/id/';
2(function($){
3  var settings = {};
4  var methods = {
5    init : function( options ) {
6      settings = $.extend({
7        'uri'   : requestUrl,
8        'conn'  : null
9      }, options);
10      $(this).chat('connect');
11    },
12    connect : function () {
13      if (settings['conn'] == null) {
14        settings['conn'] = new WebSocket(settings['uri']);
15        settings['conn'].onopen = methods['onOpen'];
16        settings['conn'].onmessage = methods['onSend'];
17        settings['conn'].onclose = methods['onClose'];
18        settings['conn'].onerror = methods['onError'];
19      }
20    },
21    onOpen : function ( event ) {
22      console.log('サーバーに接続');
23    },
24    onSend : function (event) {
25      if (event && event.data) {
26        $(this).chat('drawText',event.data);
27      }
28    },
29    onError : function(event) {
30      console.log('エラー発生');
31    },
32    onClose : function(event) {
33      console.log('サーバーと切断');
34      settings['conn'] = null;
35      setTimeout(methods['connect'], 1000);
36    },
37    drawText : function (message) {
38      $('#price').text(message);
39    },
40    parseJson : function(data){
41      returnJson = {};
42      for (idx = 0; idx < data.length; idx++) {
43        returnJson[data[idx].name] = data[idx].value
44      }
45      return returnJson;
46    },
47  }; // end of methods
48
49  $.fn.chat = function( method ) {
50    if ( methods[method] ) {
51      return methods[ method ].apply( this, Array.prototype.slice.call( arguments, 1 ));
52    } else if ( typeof method === 'object' || ! method ) {
53      return methods.init.apply( this, arguments );
54    } else {
55      $.error( 'Method ' +  method + ' does not exist' );
56    }
57  } // end of function
58})( jQuery );

Ratchetディレクトリ構成

Ratchet(root directory)
├bin
|└server.php
├src
|└chat
| └chat.php
├vendor
├composer.json
├composer.lock
└index.php

###server.php

php
1<?php
2use Ratchet\Server\IoServer;
3use chat\Chat;
4use Ratchet\Http\HttpServer;
5use Ratchet\WebSocket\WsServer;
6
7require dirname ( __DIR__ ) . '/vendor/autoload.php';
8
9$server = IoServer::factory ( new HttpServer( new WsServer( new Chat () ) ), 8080 );
10
11$server->run ();

###chat.php

php
1<?php
2namespace MyApp;
3use Ratchet\MessageComponentInterface;
4use Ratchet\ConnectionInterface;
5 
6class Chat implements MessageComponentInterface {
7    protected $clients;
8 
9    public function __construct() {
10        $this->clients = new \SplObjectStorage;
11    }
12 
13    public function onOpen(ConnectionInterface $conn) {
14        // Store the new connection to send messages to later
15        $this->clients->attach($conn);
16        
17        $conn_param = $this->parse_url_param($conn->httpRequest->getRequestTarget());
18        //個人チャットを開いたときの処理
19        if ($conn_param["mode"] == "private") {
20            //ログイン状態を確認してクライアントに送信
21            $this->login_status_send($conn, $conn_param, 'online');
22        }
23        
24        echo "New connection! ({$conn->resourceId})\n";
25    }
26 
27    public function onMessage(ConnectionInterface $from, $msg) {
28
29        $from_param = $this->parse_url_param($from->httpRequest->getRequestTarget());
30        
31        if ($from_param["mode"] == "room") {
32            foreach ($this->clients as $client) {
33                //同じルームの人対象に送信。
34                $client_param = $this->parse_url_param($client->httpRequest->getRequestTarget());
35                if ($from_param["room"] === $client_param["room"]) {
36                    $client->send($msg);
37                }
38            }
39        }
40        
41        if ($from_param["mode"] == "private") {
42          
43            $send_comp_flag = 0;
44            foreach ($this->clients as $client) {
45                //対象を指定
46                $client_param = $this->parse_url_param($client->httpRequest->getRequestTarget());
47                if ($from_param["target"] === $client_param["myself"]) {
48                    if ($from_param["myself"] === $client_param["target"]) {
49                        $client->send($msg);
50                        $send_comp_flag = 1;
51                    }
52                }
53            }
54            if ($send_comp_flag) {
55                foreach ($this->clients as $client) {
56                    //自分に送信
57                    $client_param = $this->parse_url_param($client->httpRequest->getRequestTarget());
58                    if ($from_param["target"] === $client_param["target"]) {
59                        if ($from_param["myself"] === $client_param["myself"]) {
60                            $client->send($msg);
61                        }
62                    }
63                }
64            }
65            if ($send_comp_flag == 0) {
66                $error["type"] = 'error';
67                $error["code"] = '1';
68                $error["detail"] = '相手がエラーのため送信に失敗しました';
69                $from->send(json_encode($error));
70            }
71        }
72    }
73 
74    public function onClose(ConnectionInterface $conn) {
75        // The connection is closed, remove it, as we can no longer send it messages
76        $conn_param = $this->parse_url_param($conn->httpRequest->getRequestTarget());
77
78        if ($conn_param["mode"] == "private") {// 個人チャットの場合、退室を相手に伝える
79          //ログイン状態を確認してクライアントに送信
80            $this->login_status_send($conn, $conn_param, 'offline');
81        }
82        
83        $this->clients->detach($conn);
84        echo "Connection {$conn->resourceId} has disconnected\n";
85    }
86 
87    public function onError(ConnectionInterface $conn, \Exception $e) {
88        echo "An error has occurred: {$e->getMessage()}\n";
89        $conn_param = $this->parse_url_param($conn->httpRequest->getRequestTarget());
90
91        if ($conn_param["mode"] == "private") {// 個人チャットの場合、退室を相手に伝える
92          //ログイン状態を確認してクライアントに送信
93            $this->login_status_send($conn, $conn_param, 'offline');
94        }
95        $conn->close();
96    }
97    
98    public function login_status_send(&$conn, $connect_param, $send_param) {
99      foreach ($this->clients as $client) {
100          $client_param = $this->parse_url_param($client->httpRequest->getRequestTarget());
101          if ($connect_param["target"] === $client_param["myself"]) {
102              if ($connect_param["myself"] === $client_param["target"]) {//互いにオンラインである
103                
104                  $msg["type"] = "info";
105                  $msg["status"] = $send_param;
106                  //既存入室者に、相手がオンラインになったことを伝える
107                  $client->send(json_encode($msg));
108                  //新規入室者に、相手が既にオンラインであることを伝える
109                  $conn->send(json_encode($msg));
110              }
111          }
112      }
113    }
114    
115    public function parse_url_param($string) {
116        $query = str_replace("/?", "", $string);
117        parse_str($query, $return_param);
118        return $return_param;
119    }
120}

開発環境

# OS:
$cat /etc/redhat-release
CentOS Linux release 7.8.2003 (Core)

# Apache
$httpd -v
Server version: Apache/2.4.6 (CentOS)
Server built:   Apr  2 2020 13:13:23

# PHP 
$php -v
PHP 7.3.24 (cli) (built: Oct 27 2020 11:01:59) ( NTS )
Copyright (c) 1997-2018 The PHP Group
Zend Engine v3.3.24, Copyright (c) 1998-2018 Zend Technologies

httpd.conf

httpd
1<VirtualHost *:443>
2# ServerName ipAddress:8080
3 ServerName domain.xyz:443
4 ProxyRequests Off
5<Location />
6 #Order allow, deny
7 Require all granted
8</Location>
9 <Proxy *>
10 #Order deny,allow
11 Require all granted
12 </Proxy>
13 ProxyPreserveHost On
14 ProxyPass "/ws/" "ws://domain.com:8080/"
15 ProxyPassReverse "/ws/" "ws://domain.com:8080/"
16 ProxyStatus On
17</VirtualHost>

vhost.conf

vhost
1<IfModule mod_ssl.c>
2<VirtualHost *:443>
3    SSLEngine on
4    SSLCertificateKeyFile /etc/httpd/conf/ssl.key/server.key
5    SSLCertificateFile /etc/httpd/conf/ssl.crt/server.crt
6    SSLCertificateChainFile /etc/httpd/conf/ssl.crt/internal.crt
7
8    DocumentRoot /var/www/html/
9    ServerName domain.com
10    ServerAlias domain.com
11    SSLStrictSNIVHostCheck off
12
13    <Directory "/var/www/html/">
14        Options FollowSymLinks
15        AllowOverride All
16        php_flag display_errors On
17        Require all granted
18    </Directory>
19
20    SSLProxyEngine On
21    RewriteEngine On
22
23    # When Upgrade:websocket header is present, redirect to ws
24    # Using NC flag (case-insensitive) as some browsers will pass Websocket
25    RewriteCond %{HTTP:Upgrade} =websocket [NC]
26    RewriteRule /  wss://domain:8080/$1 [P,L]
27
28    # All other requests go to http
29    ProxyPass "/" "https://domain.com"
30</VirtualHost>
31</IfModule>

ssl.conf

conf
1Listen 443
2SSLPassPhraseDialog exec:/usr/libexec/httpd-ssl-pass-dialog
3SSLSessionCache         shmcb:/run/httpd/sslcache(512000)
4SSLSessionCacheTimeout  300
5SSLRandomSeed startup file:/dev/urandom  256
6SSLRandomSeed connect builtin
7SSLCryptoDevice builtin
8SSLCertificateFile /etc/httpd/conf/ssl.crt/server.crt
9SSLCertificateKeyFile /etc/httpd/conf/ssl.key/server.key
10SSLCertificateChainFile /etc/httpd/conf/ssl.crt/internal.crt
11SSLCertificateKeyFile /etc/pki/tls/private/localhost.key