Known configuration to work with Spectrum WebApp - replace IP with your IP or hostname:
ProxyPass"/spectrum/oneclickwebapp" "https://xx.x.x.x:9443/spectrum/oneclickwebapp"
ProxyPassReverse"/spectrum/oneclickwebapp" "https://xx.x.x.x:9443/spectrum/oneclickwebapp"
ProxyPass"/""https://xx.x.x.x:8443/"
ProxyPassReverse"/""https://xx.x.x.x:8443/"
RewriteEngineOn
RewriteCond%{REQUEST_URI} "^/spectrum/oneclickwebapp/.*"
RewriteCond%{HTTP:Upgrade} =websocket
RewriteRule /(.*) wss://xx.x.x.x:9443/$1 [P,L]
RewriteCond%{REQUEST_URI} "^/spectrum/oneclickwebapp/.*"
RewriteCond%{HTTP:Upgrade} !=websocket
RewriteRule /(.*) https://xx.x.x.x:9443/$1 [P,L]
It is also suggested to update /etc/hosts file with the server names/IPs.