What a 401 From an API Relay Usually Means
A 401 from an API relay is a reason to inspect authentication before rewriting your prompt. HTTP defines it as a request that lacks valid authentication credentials for the target resource. It does not, by itself, identify which component rejected the request. Start with that distinction: understand the failure, then locate the boundary. ([rfc-editor.org](https://www.rfc-editor.org/rfc/rfc9110.html?utm_source=openai))
1. Save the evidence before changing anything
Record the timestamp, request method, destination hostname, response status, error body, and any request identifier. Capture the response headers too. Under HTTP semantics, a server generating a 401 must include a WWW-Authenticate challenge; inspect it when present, but do not make your investigation depend on a perfectly implemented response. ([rfc-editor.org](https://www.rfc-editor.org/rfc/rfc9110.html?utm_source=openai))
Keep credentials out of tickets and shared logs. Instead of attaching a complete request dump, record whether the expected authentication header was present and which secret version the application was configured to use.
2. Find the authentication boundary
Draw the actual route: application, local proxy, relay, upstream provider. Ask which component produced the response. Look for evidence in request identifiers, response branding, and relay-side logs rather than treating the status code as proof of origin.
For a CodeRelay Hub integration, verify that the configured destination is the relay rather than a provider endpoint left over from an earlier setup. Pair the intended endpoint with its intended credential. Do not send secrets to an unfamiliar hostname just to test whether they work.
3. Inspect the credential the process actually uses
Check the running application, not merely the terminal where you recently exported a variable. Inspect the configured secret source, deployment revision, and configuration precedence. Look for an empty value, surrounding quotes, trailing whitespace, or a secret reference pointing at the wrong environment.
A rejected key is a concrete possibility: Claude documents malformed, revoked, and expired keys as causes of its 401 authentication error. Treat these as checks to perform, not as proof that the relay forwards that exact error unchanged. ([platform.claude.com](https://platform.claude.com/docs/en/api/errors?utm_source=openai))
4. Verify the authentication format
Compare the outgoing request with the relay's documented authentication contract. Check the header name, authentication scheme, and credential placement. If the interface expects Authorization: Bearer followed by the key, verify that the scheme appears exactly once. Do not assume a provider-specific header is interchangeable.
OpenAI's error guide distinguishes invalid authentication from an incorrect API key. That makes request construction worth checking alongside the secret itself: replacing a key is not a substitute for inspecting how the client supplies it. ([developers.openai.com](https://developers.openai.com/api/docs/guides/error-codes?utm_source=openai))
5. Reproduce with one minimal request
Use a small, non-streaming request against a documented endpoint, with one supported model and a short input. Keep the same destination and credential as the failing application. Remove optional headers, tools, attachments, and orchestration layers from this diagnostic request.
- If the minimal request succeeds, compare its destination and authentication configuration with the application.
- If both fail, investigate their shared credential, endpoint, and account configuration.
- If only one deployment fails, compare its secret version and runtime settings with the working deployment.
6. Separate authentication from other failures
A 403 means the server refuses to fulfill the request; it is not simply another spelling of 401. Likewise, do not diagnose exhausted credit or rate limiting from a 401 alone. Read the accompanying error and consult the relay's documented mapping before changing billing settings or access permissions. ([rfc-editor.org](https://www.rfc-editor.org/rfc/rfc9110.html?utm_source=openai))
7. Repair once, then verify
After identifying the cause, correct the configuration or replace the rejected credential, then repeat the minimal request before restoring the full workflow. Avoid repeatedly retrying an unchanged request while guessing at unrelated settings.
If the failure persists, send support the sanitized error, timestamp, request identifier, endpoint path, and reproduction steps. Ask whether authentication failed at the relay boundary or during the upstream request. That question is more actionable than asking whether the model is down.
Open a free CodeRelay Hub workspace.