WebSocket

1011 Internal Error

The server is terminating the connection because it encountered an unexpected condition that prevented it from fulfilling the request.

On this page

When You See This Code

The server hit an unhandled exception or crashed while processing a WebSocket message. This is the WebSocket equivalent of HTTP 500 Internal Server Error.

How to Fix

Check the server-side application logs for stack traces and exceptions. Fix the underlying bug that caused the crash and add proper error handling around message processing.

Specification

View RFC / Specification →

Cross-Protocol Equivalents

HTTP 500 Internal Server Error

Comparisons

HTTP 500 Internal Server Error vs WebSocket 1011 Internal Error

Compare With

1000 Normal Closure 1001 Going Away 1002 Protocol Error 1003 Unsupported Data 1005 No Status Received 1006 Abnormal Closure 1007 Invalid Payload Data 1008 Policy Violation 1009 Message Too Big 1010 Mandatory Extension 1012 Service Restart 1013 Try Again Later

Guides

Debugging CORS Errors: A Developer's Guide Debugging & Troubleshooting

Debugging WebSocket Disconnections Debugging & Troubleshooting

WebSocket Close Codes: Why Your Connection Dropped Real-Time Protocols

WebSocket Authentication Patterns Real-Time Protocols

WebSocket vs Server-Sent Events: Choosing the Right Protocol Real-Time Protocols

WebRTC Signaling with SIP and WebSocket Real-Time Protocols

gRPC Streaming vs REST Polling: Real-Time Data Delivery Real-Time Protocols

MQTT Protocol: Lightweight Messaging for IoT and Real-Time Systems Real-Time Protocols

WebSocket Performance Tuning Performance & Optimization

RFC 6455: WebSocket Protocol Deep Dive Protocol Deep Dives

RFC 9114: HTTP/3 Protocol Deep Dive Protocol Deep Dives

QUIC Protocol: The Transport Layer Behind HTTP/3 Protocol Deep Dives

TLS 1.3: Faster, Simpler, More Secure Protocol Deep Dives

Migrating from WebSocket to Server-Sent Events Migration & Upgrades

Reverse Proxy Configuration: Nginx, Caddy, and HAProxy Production Infrastructure

Connection Draining: Graceful Shutdown Without Dropping Requests Production Infrastructure

API Gateway Patterns: Architecture and Use Cases API Gateway Patterns

API Gateway Request Routing: Path, Header, and Content-Based API Gateway Patterns

Request and Response Transformation at the API Gateway API Gateway Patterns

CORS Handling at the API Gateway API Gateway Patterns

API Security Testing: OWASP ZAP, Burp Suite, and Automated Scanning Testing & Mocking

Debugging Scenarios

1008 Policy Violation — Authentication Timeout Intermediate

1013 Try Again Later — Server Overloaded Intermediate

Glossary

GraphQL CORS (Cross-Origin Resource Sharing) Port Number Latency NAT (Network Address Translation) Socket Bandwidth Backpressure Thundering Herd Request-Response Model RFC (Request for Comments) Protocol Upgrade Multiplexing Message Framing Full-Duplex WebSocket Frame WebRTC (Web Real-Time Communication) Signaling ICE Candidate WebSocket Subprotocol WebSocket Ping/Pong WebSocket Close Code STUN (Session Traversal Utilities for NAT) TURN (Traversal Using Relays around NAT) SDP (Session Description Protocol) MQTT (Message Queuing Telemetry Transport) STOMP (Simple Text Oriented Messaging Protocol) RTP (Real-time Transport Protocol) Codec Negotiation

Frequently Asked Questions

What is WebSocket 1011 Internal Error?

The server is terminating the connection because it encountered an unexpected condition that prevented it from fulfilling the request.

When do you see WebSocket 1011 Internal Error?

The server hit an unhandled exception or crashed while processing a WebSocket message. This is the WebSocket equivalent of HTTP 500 Internal Server Error.

How to fix WebSocket 1011 Internal Error?

Check the server-side application logs for stack traces and exceptions. Fix the underlying bug that caused the crash and add proper error handling around message processing.