Troubleshooting WebSocket | Missing upgrade headers

Issue

Adobe logs have shown increased HTTP 400 errors for WebSocket endpoints with Adobe Express. The error response indicates missing Upgrade headers in client connection requests.

Enterprise clients may see these 400 responses when trying to establish WebSocket connections.

The error can be due to how an enterprise environment is configured to use a proxy server.

Resolution

If your enterprise environment involves WebSocket APIs, we recommend the Upgrade header is considered a hop-by-hop header in the proxy configuration.

Further details on WebSocket proxying are available here.

References

https://helpx.adobe.com/uk/download-install/using/proxy-authentication-support.html

http://nginx.org/en/docs/http/websocket.html