Troubleshooting Guide: Resolving WebSocket's Closing or Closed State Issues

WebSockets provide real-time, two-way communication between a client and a server. However, sometimes you might encounter issues with WebSockets closing or entering a closed state. In this guide, we will explore some common issues and their solutions when working with WebSockets, particularly concerning the closing or closed state.

Table of Contents

  1. Understanding WebSocket States
  2. Identifying Common Issues
  3. Step-by-Step Solutions
  4. Issue 1: Network Problems
  5. Issue 2: Server-Side Configuration
  6. Issue 3: Client-Side Configuration
  7. Issue 4: WebSocket Timeout
  8. Issue 5: Firewall or Proxy Restrictions
  9. FAQs

Understanding WebSocket States

Before diving into troubleshooting, it's essential to understand the different WebSocket states. There are four primary states:

  1. Connecting (0): The initial state when establishing a WebSocket connection.
  2. Open (1): The connection is established, and data can be sent and received.
  3. Closing (2): The connection is in the process of closing.
  4. Closed (3): The connection is closed or couldn't be opened.

When a WebSocket enters the closing or closed state, it's essential to identify the root cause to resolve the issue effectively.

Identifying Common Issues

There are several common issues that might cause a WebSocket to enter the closing or closed state, including:

  1. Network problems
  2. Server-side configuration issues
  3. Client-side configuration issues
  4. WebSocket timeout
  5. Firewall or proxy restrictions

Step-by-Step Solutions

Issue 1: Network Problems

Step 1: Check your network connection

Ensure that your device is connected to the internet and has a stable connection.

Step 2: Ping the WebSocket server

Use the ping command to check the connection to the WebSocket server. If the server is unreachable, there might be a problem with the server or network.

Issue 2: Server-Side Configuration

Step 1: Check server logs

Inspect the server logs for any error messages or issues related to WebSocket connections.

Step 2: Verify WebSocket support is enabled

Ensure that your server supports WebSocket connections and is properly configured to handle them.

Step 3: Test with another WebSocket server

Try connecting to a different WebSocket server to rule out server-specific issues.

Issue 3: Client-Side Configuration

Step 1: Verify browser support

Ensure that your browser supports WebSocket connections. You can check browser compatibility on websites like Can I use.

Step 2: Check for client-side errors

Inspect the browser's console for any error messages or issues related to WebSocket connections.

Step 3: Test with another client

Try connecting to the WebSocket server with a different client to rule out client-specific issues.

Issue 4: WebSocket Timeout

Step 1: Adjust server-side timeout settings

Increase the server-side timeout settings to allow for a longer duration before the WebSocket connection is closed.

Step 2: Implement client-side keep-alive messages

Implement keep-alive messages from the client to the server to keep the connection alive and prevent timeouts.

Issue 5: Firewall or Proxy Restrictions

Step 1: Check firewall settings

Ensure that your firewall allows WebSocket connections and is not blocking them.

Step 2: Verify proxy settings

If you are using a proxy server, ensure that it supports WebSocket connections and is properly configured.

Step 3: Test without a firewall or proxy

Temporarily disable your firewall or proxy to test if the WebSocket connection works without them.


What are the primary WebSocket states?

There are four primary WebSocket states:

  1. Connecting (0)
  2. Open (1)
  3. Closing (2)
  4. Closed (3)

How do I check if my browser supports WebSockets?

You can check browser compatibility for WebSockets on websites like Can I use.

What is a WebSocket timeout?

A WebSocket timeout occurs when there is no activity on a WebSocket connection for a specified duration, causing the connection to close.

Can firewalls or proxies cause WebSocket issues?

Yes, firewalls or proxies can cause WebSocket issues if they are not properly configured to allow WebSocket connections.

How do I keep a WebSocket connection alive?

To keep a WebSocket connection alive, you can implement client-side keep-alive messages that are regularly sent to the server.

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