A 401 response at the relay

Wire formatsEN2026-10-28

You send a request, wait for an answer, and receive 401 Unauthorized. There is no model response, just a status code and perhaps a short error message. For a first API call, this can feel unhelpfully terse.

A 401 usually means the service handling the request could not accept its authentication credentials. The key might be missing, invalid, expired, or intended for a different service. Despite the word “Unauthorized,” the first thing to investigate is whether the request successfully identified your account.

With a relay, there is one extra question: which service rejected the credentials?

§ The two connections behind one request

A relay accepts your request and forwards it to a model provider. That creates two connections: your application to the relay, and the relay to the provider. Authentication happens along that path, and a visible error may originate at either connection.

Vana API provides one endpoint, https://api.vanaapi.com, with support for the OpenAI-compatible interface, Anthropic Messages, and Gemini native protocols. Your application authenticates to Vana API using the credentials intended for that service. The relay then handles its connection to the selected provider.

A 401 alone does not establish which connection failed. Read the response body alongside the status code. It may identify a missing key, an invalid credential, or an upstream authentication problem. The wording and amount of detail vary between services.

§ Start with the key and destination

Check the destination before replacing anything. An SDK may still be using its default provider address even after you added a relay key. A valid key sent to the wrong service can produce the same status as an invalid key sent to the right one.

For Vana API, confirm that the configured host is https://api.vanaapi.com. Also check the base path expected by your SDK. Some clients expect a versioned API base, while others add the version and resource path themselves. Follow the setup instructions for your particular client.

Then inspect how the running application receives its key:

Confirm that the key belongs to the relay account you intend to use.
Check that the environment variable or configuration field contains a value.
Look for copied spaces, line breaks, or quotation marks that became part of the value.
If you replaced the key, restart the process so it loads the updated setting.

A variable saved in one terminal may be absent in another. An editor, background service, or container may also have a different environment from your shell. Check the configuration used by the process making the request.

§ Check the authentication format

For an OpenAI-compatible request, authentication commonly uses an Authorization header whose value starts with Bearer, followed by a space and the API key. An SDK usually constructs this header from its API key setting.

Other protocols can use different authentication headers. Do not assume that a manually assembled Anthropic Messages or Gemini native request should copy every header from an OpenAI-compatible example. Use the relay’s instructions for the protocol you selected.

When debugging, record whether the expected header exists, but keep its value out of screenshots, shared logs, and support messages. If a key has been exposed, revoke it and create a replacement.

§ Make the next attempt smaller

Try one minimal request using a documented client configuration and a model available to your account, such as Gemini 2.5 Flash. Leave out optional tools, attachments, and extra application layers. Change one setting at a time so you can tell which change mattered.

Repeating an unchanged request rarely resolves a missing or invalid credential. If the response explicitly identifies an upstream authentication failure, the relay operator may need to investigate. Keep the request time, status, error message, and request identifier, if supplied, for support.

If you are starting with Vana API, create an account to obtain your API credentials and follow the setup instructions for your client. A successful small request gives you a useful baseline: a working destination, a recognized key, and a configuration you can return to when a larger application fails.