Hi,
I'v tested again and this config is OK for proxying proxmox (including vnc): <VirtualHost *:443> ServerName <Extern.Sitename.de> ErrorLog ${APACHE_LOG_DIR}/Proxy_<Extern.Sitename.de>_error.log CustomLog ${APACHE_LOG_DIR}/Proxy_<Extern.Sitename.de>_access.log combined UseCanonicalPhysicalPort Off UseCanonicalName Off DocumentRoot /var/www/html/ SSLEngine on SSLCertificateFile /etc/letsencrypt/live/<Extern.Sitename.de>/fullchain.pem SSLCertificateKeyFile /etc/letsencrypt/live/<Extern.Sitename.de>/privkey.pem ProxyRequests Off ProxyPreserveHost On #SSL Connect SSLProxyVerify none SSLProxyCheckPeerCN off SSLProxyCheckPeerName off SSLProxyCheckPeerExpire off # HSTS (mod_headers is required) (15768000 seconds = 6 months) #Header always set Strict-Transport-Security "max-age=15768000" # Encoded slashes need to be allowed AllowEncodedSlashes NoDecode RewriteEngine on RewriteCond %{HTTP:Connection <HTTP:Connection> } Upgrade [NC] RewriteCond %{HTTP:Upgrade <HTTP:Upgrade> } websocket [NC] RewriteRule /(.*) wss://127.0.0.1:8006/$1 [P,L] SSLProxyEngine on ProxyRequests off #block Proxy for letsencrypt verification! ProxyPass /.wellknown ! ProxyPass / https://127.0.0.1:8006/ flushpackets=On connectiontimeout=300 timeout=300 ProxyPassReverse / https://127.0.0.1:8006/ ProxyTimeout 600 </VirtualHost>