No realtime update of incoming and outgoing messages - websockets work

Fresh plain vanilla installation on:

• CentOS 10 Stream
• MongoDB 7.0.16
• NodeJS 22.11.0
• Deno 1.46.3
• EPEL - Extra Packages for Enterprise Linux - epel-release 10-2-el10s
• RocketChat 7.3.0
• Apache Reverse Proxy to terminate https/wss on a separate machine

Rocketchat works so far but does not update incoming and outgoing messages in real time. The outgoing message stays grayed out until the next page reload. An incoming message rings the notification bell but does not appear on screen until reload.

• Websockets are configured and work - as checked with WS-Tester. In the Browser Network Analysis the WS connection is open, transmits 175bytes and stays idle.
• The RocketChat Log says "No real time data received recently" (could be a subsequent issue)
• a message sent results in a single http(s) sendMessage call, which gets replied to correctly with an JSON document. Incoming calls do not result in any action.

Apache Proxy Configuration:

ProxyPreserveHost On
RemoteIPHeader X-Forwarded-For

<Location / >
                Order allow,deny
                Allow from all

                ProxyPass http://rocketchat-virt:3000/
                ProxyPassReverse http://rocketchat-virt:3000/
</Location>

RewriteEngine On
RewriteCond %{HTTP:Upgrade} =websocket [NC]
RewriteCond %{HTTP:Connection} upgrade [NC]
RewriteRule ^/(.*) "ws://rocketchat-virt:3000/$1" [P,L]

What's wrong here?

This still can be a configuration issue both in the Proxy settings or RocketChat itself - so I'd be interested in further documentation.

Thank You in advance
Conrad

Start by reviewing the Apache reverse-proxy and websocket RewriteRule configuration together with the Browser Network Analysis and Rocket.Chat log observations. Reproduce the missing realtime updates on the listed installation versions, then determine whether the cause is proxy configuration or Rocket.Chat and document the confirmed fix or required configuration.