OpenRouter / Cloud Platforms

OpenRouter returns 401 Missing Authentication header in OpenClaw and LiteLLM chains

Fix OpenRouter 401 Missing Authentication header error in proxy chains Includes evidence for OpenRouter troubleshooting demand.

Source-backed Last updated May 11, 2026 1 source Needs local verification

Category: Cloud Platforms
Error signature: 401 Missing Authentication header
Quick fix: Verify the account session, API key, provider settings, and environment where the failing tool is running.
Updated: May 11, 2026
Verification status: Source-backed
Evidence: 1 public source URL

Before you change production

This page includes public source URLs in the imported troubleshooting record. Compare those references with your version and environment before applying changes.

Reproduce the smallest failing action and save non-secret logs before changing configuration.
Check versions for OpenRouter, related SDKs, package managers, CI runners, and hosting providers.
Change one setting or dependency at a time, then rerun the same failing command or request.
Avoid destructive commands, credential rotation, billing changes, or security relaxations without a rollback plan.

What this error means

401 Missing Authentication header is a OpenRouter failure pattern reported for developers trying to fix openrouter 401 missing authentication header error in proxy chains. Based on the imported evidence, treat this as a tool-specific troubleshooting page rather than a generic API error.

Why this happens

GitHub issue #51056 shows OpenRouter returning '401 Missing Authentication header' in a proxy chain (openclaw -> openrouter). Error occurs during auth step taking 694ms, with any openrouter model affected.

Common causes

Occurs specifically in proxy routing chains (e.g., openclaw -> openrouter). The error indicates the authentication header is being dropped during routing — a common but hard-to-debug issue for developers using multi-provider setups.
GitHub issue #51056 shows OpenRouter returning '401 Missing Authentication header' in a proxy chain (openclaw -> openrouter). Error occurs during auth step taking 694ms, with any openrouter model affected.

Quick fixes

Confirm the exact error signature matches 401 Missing Authentication header.
Check the OpenRouter account, local tool state, and provider configuration involved in the failing workflow.
Verify the account session, API key, provider settings, and environment where the failing tool is running.

Platform/tool-specific checks

Verify the command, editor, extension, or API client that produced the error.
Compare local settings with CI, deployment, or editor-level settings when the error appears in only one environment.
Avoid deleting credentials, local model data, or project settings until the failing scope is clear.

Step-by-step troubleshooting

Capture the exact error message and the command, editor action, or request that triggered it.
Check whether the failure is account/auth, quota/rate, model/provider, local runtime, or deployment configuration.
Review the source evidence below and compare it with your environment.
Apply one change at a time and rerun the smallest failing action.
Keep the working fix documented for the team or deployment environment.

How to prevent it

Keep provider/tool configuration documented.
Record non-secret diagnostics such as tool version, provider name, model name, and command path.
Add a lightweight check before CI or production workflows depend on the tool.

Diagnostic flow for this page

Match 401 Missing Authentication header exactly before applying the quick fix.
Compare the failing environment with OpenRouter versions, account scope, provider settings, and deployment context.
Check the listed common causes in order, starting with the cause that best matches your logs.
Use the evidence status below to decide whether to confirm against public sources or official documentation.
Apply one reversible change, rerun the smallest failing action, and keep rollback notes.

FAQ

What does 401 Missing Authentication header mean in OpenRouter?

401 Missing Authentication header indicates the workflow described by "OpenRouter returns 401 Missing Authentication header in OpenClaw and LiteLLM chains" failed in a Cloud Platforms context. Start by confirming the exact signature and the component that emitted it.

What should I check first for 401 Missing Authentication header?

Check whether this cause matches your environment: Occurs specifically in proxy routing chains (e.g., openclaw -> openrouter). The error indicates the authentication header is being dropped during routing — a common but hard-to-debug issue for developers using multi-provider setups.

Is the 401 Missing Authentication header guidance source-backed?

The "OpenRouter returns 401 Missing Authentication header in OpenClaw and LiteLLM chains" page is labeled source-backed. It has 1 public source URL from github.com, so use that evidence status when deciding how much additional verification you need.

When should I avoid the quick fix for 401 Missing Authentication header?

For "OpenRouter returns 401 Missing Authentication header in OpenClaw and LiteLLM chains", avoid applying "Verify the account session, API key, provider settings, and environment where the failing tool is running." when the error text differs, the affected version or provider is different, or the change would touch credentials, billing, DNS, production deploy settings, or irreversible data.

What should I collect before debugging 401 Missing Authentication header?

For "OpenRouter returns 401 Missing Authentication header in OpenClaw and LiteLLM chains", collect the failing OpenRouter command or request, non-secret configuration, versions, timestamps, request IDs when available, and the smallest reproduction that still triggers the signature.