javascript
WebSocket handshake failure
WebSocket.*handshake.*failed|Error during WebSocket handshake|unexpected response code: 4\d{2}
Fixes
- 1.Ensure the server responds with HTTP 101 Switching Protocols — check for middleware intercepting the upgrade
- 2.Verify proxy is configured for WebSocket: proxy_http_version 1.1; proxy_set_header Upgrade $http_upgrade; proxy_set_header Connection 'upgrade'
- 3.Check that the Origin header is allowed by the server's CORS/origin validation
websockethandshakeupgrade
Related Errors
javascript3 fixes
Cannot read property of undefined
Cannot read propert(y|ies) of undefined
- •Add optional chaining (?.)
- •Check if object exists before accessing
javascript3 fixes
Cannot read property of null
Cannot read propert(y|ies) of null
- •Add null check before access
- •Use optional chaining (?.)
javascript3 fixes
TypeError: X is not a function
is not a function
- •Check spelling of method name
- •Verify import is correct