Claude Code Error: Connection Timeout During Task Fix

Connection timeout errors in Claude Code can interrupt your workflow during critical development tasks. When the CLI cannot establish or maintain a connection to Anthropic’s API servers, tasks fail mid-execution, leaving incomplete work and frustrating error messages. This guide provides practical solutions for developers and power users facing these timeout issues.

Understanding Connection Timeout Errors

A connection timeout occurs when Claude Code fails to establish a network connection within the expected time frame. The error typically manifests as:

Error: Connection timeout after 120000ms

or

Claude Code API request failed: connect ETIMEDOUT

These errors can occur during initial connection, between API calls in long-running tasks, or when processing large responses. Understanding the root cause helps you apply the right fix.

Common Causes and Solutions

1. Network Configuration Issues

The most frequent cause of connection timeouts is network configuration. Claude Code communicates with Anthropic’s servers over HTTPS, requiring proper DNS resolution and network routing.

Diagnose the issue:

# Test connectivity to Anthropic's API endpoint
curl -I https://api.anthropic.com

# Test DNS resolution
nslookup api.anthropic.com

# Check your default gateway
route -n get default

Solution: If you use a corporate VPN or firewall, ensure it allows outbound HTTPS traffic to api.anthropic.com. Some users benefit from configuring a custom DNS server like Cloudflare (1.1.1.1) or Google (8.8.8.8).

2. API Key and Authentication Problems

Expired or incorrectly configured API keys can cause connection attempts to fail silently or timeout while waiting for authentication.

Verify your API key:

# Check if ANTHROPIC_API_KEY is set
echo $ANTHROPIC_API_KEY

# Set the API key explicitly for the current session
export ANTHROPIC_API_KEY="sk-ant-api03-your-key-here"

Solution: Generate a fresh API key from the Anthropic console and ensure it has the correct permissions. The environment variable should be set before invoking Claude Code.

3. Request Timeout Configuration

For tasks that involve large file processing or complex operations—common when using skills like pdf for document analysis or frontend-design for UI prototyping—the default timeout may be insufficient.

Increase timeout in your configuration:

# Set a custom timeout (in seconds)
export CLAUDE_TIMEOUT=300

# Or pass it directly to the command
claude --print "your task here"

Solution: Adjust the ANTHROPIC_TIMEOUT environment variable or use the --timeout flag. Values between 180 and 600 seconds work well for complex tasks.

4. Proxy and TLS Inspection Issues

Corporate proxies and TLS inspection tools can interfere with HTTPS connections, causing unexpected timeouts or connection failures.

Test direct connection (bypassing proxy):

# Temporarily unset proxy variables
unset http_proxy https_proxy HTTP_PROXY HTTPS_PROXY

# Run your task
claude "your task"

Solution: If a proxy is required for internet access, configure it properly:

export HTTP_PROXY=http://proxy.example.com:8080
export HTTPS_PROXY=http://proxy.example.com:8080
export NO_PROXY=localhost,127.0.0.1

For TLS inspection issues, you may need to add your corporate certificate to the system trust store or disable inspection for api.anthropic.com.

5. Rate Limiting and Server Issues

Anthropic implements rate limiting that can manifest as timeouts when you exceed allowed request frequency.

Check your rate limit status:

# View current rate limit headers in API responses
claude --verbose "your task" 2>&1 | grep -i rate

Solution: Implement exponential backoff in your automation scripts. If you consistently hit limits, consider upgrading your plan or distributing requests across multiple API keys.

Working with Claude Skills During Timeout Issues

When connection timeouts occur during skill execution—perhaps while using tdd for test-driven development or supermemory for knowledge retrieval—the partial state can complicate recovery.

Resume interrupted tasks:

# Use the continue flag to resume
claude --continue "continue the previous task"

# Or specify a checkpoint file
claude --continue

Best practice: Break large tasks into smaller steps when working with skills. This reduces the impact of timeouts and makes recovery easier.

Performance Optimization for Complex Tasks

Prevent timeouts by optimizing how you structure complex tasks:

Chunk Large Operations

Instead of processing an entire codebase:

# Process files in batches
find ./src -name "*.ts" | head -10 | xargs -I {} claude "analyze {}"

Use Streaming Responsibly

Skills that generate large outputs—like those using algorithmic-art or canvas-design—may benefit from streaming disabled:

claude --print "generate the design"

Configure Retry Behavior

Add automatic retries for transient failures:

# Shell wrapper with retry logic
retry_claude() {
    local attempt=1
    while [ $attempt -le 3 ]; do
        claude "$@" && return 0
        echo "Attempt $attempt failed, retrying..."
        attempt=$((attempt + 1))
        sleep 5
    done
    echo "All attempts failed"
    return 1
}

Debugging Tools and Techniques

When standard fixes don’t resolve the issue, use detailed debugging:

# Enable debug output
export DEBUG=claude:*

# Run with verbose logging
claude --verbose --debug "your task"

Network-level debugging helps identify where connections fail:

# Trace the connection path
traceroute -I api.anthropic.com

# Or use mtr for more detailed analysis
mtr api.anthropic.com

Prevention Strategies

1. Monitor network health before starting large tasks
2. Keep Claude Code updated for the latest connection handling improvements
3. Use checkpoint files for long-running operations
4. Maintain multiple authentication methods (API key rotation)
5. Implement health checks in automation scripts:

# Quick health check before main task
curl -s -o /dev/null -w "%{http_code}" https://api.anthropic.com && \
    claude "your task" || \
    echo "Connection check failed"

When to Seek Additional Help

If you’ve tried these solutions and still experience timeout errors:

• Check Anthropic’s status page for outages
• Review your account for any API key restrictions
• Consider geographic latency—users in some regions benefit from using regional API endpoints

Connection timeout errors in Claude Code are typically resolvable through proper configuration, network settings, or timeout adjustments. By understanding the underlying causes and implementing these fixes, you can maintain productive workflows without interruption.

Related Reading

• Claude Code Not Responding Terminal Hangs Fix — Related: terminal hang vs timeout distinction
• Claude Code Slow Response How to Fix Latency Issues — Performance and network issues guide
• Claude Code Error Rate Limit 429 How to Handle — Another API error that affects connectivity
• Claude Skills Troubleshooting Hub — All Claude Code error and connectivity fixes

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