Failed-error-during-websocket-handshake-connection-header-is-missing -

Ensure mod_proxy and mod_proxy_wstunnel are enabled. Use a RewriteRule in your VirtualHost to pass WebSocket traffic:

: Force websocket transport: io('url', { transports: ['websocket'] }) . Ensure mod_proxy and mod_proxy_wstunnel are enabled

The error occurs when a client tries to establish a WebSocket connection, but a network intermediary (like a reverse proxy or load balancer) strips out the required HTTP headers needed to upgrade the connection from standard HTTP to WebSockets . Ensure mod_proxy and mod_proxy_wstunnel are enabled