Use the Token Factory API key for inference calls, never the IAM token - they are different credentials for different surfaces. Before debugging code, list the models endpoint with your key to confirm both auth and which models your project can reach. Confirm the project has inference and billing entitlement enabled, since a rejected request is often an entitlement gap rather than a bug.

Context: Nebius Token Factory troubleshooting docs document the key confusion that causes most auth failures. If authentication fails, check that you supplied the Token Factory key and not an IAM token; also check revocation and project access. When a model or inference request is rejected, check the models list, the returned error, and your project's inference and billing entitlement. Workflow runs that say the key is required need the key passed as a secret env on submit.