Troubleshooting 401 Unauthorized When Calling OpenAI Compatible APIs

First Locate the Issue with a Single Command

Run the following command to test:

curl -sS -i https://api.treenew.online/v1/chat/completions \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model":"gpt-5.6-luna","messages":[{"role":"user","content":"hi"}],"max_tokens":1}'

max_tokens: 1 is deliberate: this call only needs to prove authentication works, so the cost is negligible.

Reading the result:

• HTTP 401 — the Key or the Authorization header is at fault, not your client. Continue to the checklist below.
• HTTP 200 — the Key is fine; the problem is in your client configuration (wrong base URL, the Key never got saved, an environment variable overriding it, and so on).
• 404 saying the model does not exist — authentication actually succeeded; that is a different problem, see Model Not Found.

Running this one command first saves most of the guesswork.

Check Item by Item

• Missing or Incorrect Bearer Prefix: Verify the header is exactly Authorization: Bearer sk-xxx. Rule out a missing prefix, lowercase bearer, or using Basic.
• Whitespace or Newlines in the Key: After copying the Key from the console, trim it to remove any leading or trailing whitespace characters.
• Using Login Password Instead of Token: Confirm the Key was created on the https://api.treenew.online Token page, not your account login password.
• Token Deleted/Expired/Disabled: Log in to the console and check the token status. Exhausting quota can cause the token to be disabled.
• Token IP or Model Whitelist Mismatch: Check the token binding settings to ensure the current IP and requested model match the whitelist.
• Key Placed in the Wrong Field (e.g. Base URL): Base URL must be set to https://api.treenew.online/v1. The Key belongs only in the Authorization header.
• Key Changes Not Taking Effect Due to Client Storage: After updating the Key, restart the client. Check whether environment variables or caches are overriding the new value.

Difference Between 401 and 403

401 means authentication information is invalid or missing. 403 means authentication succeeded but access is denied. The troubleshooting approaches differ.

Still Not Working

Collect the desensitized request headers (with Key value hidden), request timestamp, and token name for feedback.

See also

• OpenAI-compatible setup
• 429 rate limits
• Model not found