Using Apache 2.4, I have a websocket server on localhost at port 1234, accessed through a virtual host on port 443. It all works, which is surprising because my error log is filling up with messages:

[Tue Jul 27 23:09:20.574164 2021] [proxy:error] [pid 3112:tid 140321405003520] (111)Connection refused: AH00957: ws: attempt to connect to 35.177.28.97:1234 (prsm.uk) failed
[Tue Jul 27 23:09:20.574208 2021] [proxy_http:error] [pid 3112:tid 140321405003520] [client 80.2.127.158:49843] AH01114: HTTP: failed to make connection to backend: prsm.uk

The server is a Linux 2 instance on AWS EC2. The .conf file for the virtual host is:

<VirtualHost *:80>
        ServerName www.prsm.uk
        ServerAlias prsm.uk
    Redirect / https://www.prsm.uk/
</VirtualHost>
<VirtualHost *:443>
        ServerName www.prsm.uk
        ServerAlias prsm.uk
         DocumentRoot "/data/prsm"
        DirectoryIndex "index.html" "index.php" "index.htm"
        <Directory "/data/prsm">
                Options MultiViews FollowSymLinks
                AllowOverride  All
                Require all granted
        </Directory>

    SSLProxyEngine on
        ProxyPass /wss  ws://localhost:1234

        SSLEngine on
    SSLProtocol TLSv1.2
        SSLCipherSuite HIGH:MEDIUM:!aNULL:!MD5
        SSLCertificateFile "/etc/letsencrypt/live/www.prsm.uk/fullchain.pem"
        SSLCertificateKeyFile "/etc/letsencrypt/live/www.prsm.uk/privkey.pem"
        <FilesMatch "\.(cgi|shtml|phtml|php)$">
                SSLOptions +StdEnvVars
        </FilesMatch>
        BrowserMatch "MSIE [2-5]" \
                         nokeepalive ssl-unclean-shutdown \
                         downgrade-1.0 force-response-1.0

</VirtualHost>

The AWS Security Group is currently configured to let all inward bound access to port 1234 (and ports 80 and 443).

Why am I getting these error messages and what should I do to get rid of them?

(In case it matters, SeLinux is disabled on AWS LInux 2, and it seems that enabling it would be unsupported and unwise).