Fix Browser “xhr poll” Error Free PBX

Each time I open my UCP in a web browser I immediately see the message “Unable to connect to the UCP Node Server. Error: xhr poll error.” Because the error shows up at page load—before any clicks or interaction—I’m convinced the problem sits in the initial Socket.IO long-polling or WebSocket handshake between the browser and my Node-based server.

I need a developer who can trace the fault, correct whatever is blocking or mis-configuring the connection, and leave the panel loading cleanly for every visitor. Possible culprits include CORS rules, transport fallbacks, reverse-proxy headers, SSL termination, or even a firewall that drops the polling request; I’m open to any solution that gets rid of the error without breaking existing features.

Deliverables
• Diagnose the root cause using browser dev-tools, server logs, and your preferred debugging stack
• Patch the Node server code and/or proxy configuration so the browser connects on the first try
• Provide a concise change log and verification steps showing the page now loads with no “xhr poll error”

If you have recent experience fixing Socket.IO or similar real-time Node issues, this should be a quick win.