How to run websockets on Apache via wss? - apache

Question

I am trying to run a PHP chat on sockets.
Server configuration: Ubuntu-18.04-amd64, Apache/2.4.29, SSL certificate from Let's Encrypt.
I use rachet. Here, here and here it is described how to connect sockets through SSL connections. But I didn’t succeed.
I installed the necessary modules in Apache:
sudo a2enmod proxy
sudo a2enmod proxy_wstunnel
sudo a2enmod proxy_http
Wrote in /etc/apache2/apache2.conf
<VirtualHost *: 443>
<Location "/chat/">
ProxyPreserveHost On
ProxyPass /ws ws://xxxxxx.xx:999
ProxyPassReverse /ws ws://xxxxxx.xx:999
</Location>
</VirtualHost>
Opened 999 port
sudo iptables -I INPUT -p tcp --dport 999 -j ACCEPT
Restarted Apache
sudo systemctl restart apache2
Launched a chat server
php /var/www/html/chat/bin/chat-server.php
Wrote in the socket call script
websocket = new WebSocket ('wss://xxxxxx.xx/chat');
I tried to connect from a browser at
https://xxxxxx.xx/chat/
And got an error
WebSocket connection to 'wss://xxxxxx.xx/chat' failed: Error during
WebSocket handshake: Unexpected response code: 301
I read various tips, but still could not understand what I was doing wrong. Any attempt to change the situation creates errors 301, 300, 500 or 200.
Please tell me what I was wrong?