Why Does the WebSocket Handshake Fail Only in Chromium Browsers?

Below is some guidance on troubleshooting this error. Although this issue isn't directly covered in the n8n documentation, similar reverse proxy configuration challenges have been encountered by users.

What's Happening

The error message indicates that during the WebSocket handshake, Chromium expects the Connection header to include the Upgrade token. In your case, it appears that even though you've set headers in OpenLiteSpeed, the necessary headers for establishing a WebSocket connection may not be forwarded correctly.

What to Check

1. Reverse Proxy Configuration:
   Make sure that OpenLiteSpeed is not only setting the header but also passing through any necessary WebSocket-specific headers. Typical headers for a WebSocket upgrade include:

   • Upgrade: websocket
   • Connection: Upgrade
   • Additionally, ensure that headers like Sec-Websocket-Key and Sec-Websocket-Version are not removed or modified.

2. Proxy Rules for WebSockets:
   Some reverse proxies require explicit configuration for handling WebSocket connections. Verify your OpenLiteSpeed settings to ensure that WebSocket upgrade requests are properly detected and proxied to your n8n instance.

3. Environment Variables (If Running Behind a Proxy):
   If you’re running n8n behind a reverse proxy, ensure the environment variable N8N_PROXY_HOPS (if applicable) is set to the correct number of proxy layers. This setting helps n8n to correctly identify the original client IP, though its absence is less likely to cause header issues with WebSocket upgrades.

Additional Steps

• Review WebSocket Documentation:
  Double-check OpenLiteSpeed’s documentation for handling WebSocket upgrade requests. There might be specific examples or settings required in your server configuration.

• Test Direct Connection:
  If possible, try connecting to n8n directly (bypassing the reverse proxy) to determine if the issue lies with the proxy configuration rather than n8n itself.

• Compare Firefox vs Chromium Behavior:
  Since Firefox is handling the connection correctly, compare the network request/response headers between Firefox and Chromium. This might provide a clue if Chromium is stricter about certain header values.

Example Header Configuration

Below is a typical configuration snippet you might expect in a reverse proxy setup. (The exact configuration syntax may differ in OpenLiteSpeed.)

NGINXCopied
location /rest/push/ {
    proxy_pass http://your_n8n_backend;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "Upgrade";
    proxy_http_version 1.1;
}

While this example is written in an nginx-like syntax, the same principles apply for OpenLiteSpeed—be sure to set the Upgrade and Connection headers appropriately.

If you continue having difficulties, consider reaching out to the OpenLiteSpeed community or consulting their documentation for additional details on enabling WebSocket support.

Hope this helps resolve the issue!