Claude Code Unable to Connect to API

If Claude Code cannot connect to the API, times out, or reports SSL certificate problems, treat it as a network path issue first. The cause may be local connectivity, corporate proxy inspection, VPN routing, certificate trust, provider status, or an incorrect base URL.

Quick Checks

1. Check whether Claude service status or your provider status page shows an incident.
2. Try a simple network request from the same terminal environment.
3. If you use a proxy, confirm HTTP_PROXY, HTTPS_PROXY, and certificate settings.
4. If you use a custom gateway or provider, verify ANTHROPIC_BASE_URL and related credentials.
5. Retry from a different network before reinstalling Claude Code.

Common Causes

Corporate networks may intercept TLS, block download or API hosts, or require a custom CA certificate. VPNs can also route browser traffic differently from terminal traffic. In cloud-provider setups, the error may come from Bedrock, Vertex, Foundry, or a custom gateway rather than Anthropic directly.

When To Escalate

Record the exact error text, operating system, shell, proxy or VPN state, active credential path, and whether the same request works from another network. If Claude Code starts, run /doctor; if it cannot start, run claude doctor from the shell.

Related Pages

• Login or authentication error
• Claude command not found
• Claude Code troubleshooting hub
• Claude Code API reference hub

Official Sources

• Claude Code error reference
• Troubleshoot installation and login