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 .
If you are using Nginx as a reverse proxy, you must explicitly tell it to forward the Upgrade and Connection headers. By default, Nginx does not do this. Add or update your location block in your nginx.conf file:
Managed services often strip headers; ensure WebSocket support is enabled: : Enable Stickiness for polling fallbacks. Azure App Service : Toggle WebSockets on in configuration. 💻 Local Development Protocol : Ensure using ws:// or wss:// .
Ensure mod_proxy and mod_proxy_wstunnel are enabled. Use a RewriteRule in your VirtualHost to pass WebSocket traffic:
location /ws { proxy_pass http://your_backend_server; proxy_http_version 1.1; proxy_set_header Upgrade $http_upgrade; proxy_set_header Connection "upgrade"; } Use code with caution. Copied to clipboard 🕸️ Apache Configuration Fix
Here are the most common solutions based on your infrastructure: 🚀 Nginx Configuration Fix
Which or server framework are you currently using to host this application?
RewriteCond %{HTTP:Upgrade} websocket [NC] RewriteCond %{HTTP:Connection} upgrade [NC] RewriteRule /(.*) ws://localhost:8080/$1 [P,L] Use code with caution. Copied to clipboard ☁️ Cloud Providers & Load Balancers
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 .
If you are using Nginx as a reverse proxy, you must explicitly tell it to forward the Upgrade and Connection headers. By default, Nginx does not do this. Add or update your location block in your nginx.conf file:
Managed services often strip headers; ensure WebSocket support is enabled: : Enable Stickiness for polling fallbacks. Azure App Service : Toggle WebSockets on in configuration. 💻 Local Development Protocol : Ensure using ws:// or wss:// . The error occurs when a client tries to
Ensure mod_proxy and mod_proxy_wstunnel are enabled. Use a RewriteRule in your VirtualHost to pass WebSocket traffic:
location /ws { proxy_pass http://your_backend_server; proxy_http_version 1.1; proxy_set_header Upgrade $http_upgrade; proxy_set_header Connection "upgrade"; } Use code with caution. Copied to clipboard 🕸️ Apache Configuration Fix Add or update your location block in your nginx
Here are the most common solutions based on your infrastructure: 🚀 Nginx Configuration Fix