Check response.okfetch does not reject on 404 or 500 — without this the error is swallowed. try / catchCatches network failures, DNS errors and aborts. Timeout via AbortSignalfetch has no built-in timeout and will otherwise hang indefinitely. Retry with backoff Parse the error response bodyMost APIs return a useful JSON message alongside a 4xx. Send cookies (credentials: include) Read the token from an env variable