if cred.AccessKey != accessKey {
		if !globalIAMSys.Initialized() {
			// Check if server has initialized, then only proceed
			// to check for IAM users otherwise its okay for clients
			// to retry with 503 errors when server is coming up.
			return auth.Credentials{}, false, ErrIAMNotInitialized
		}

		// Check if the access key is part of users credentials.
		u, ok, err := globalIAMSys.CheckKey(r.Context(), accessKey)

      MockResponse
        .Builder()
        .code(503)
        .addHeader("Connection", "Close")
        .addHeader("Retry-After", "0")
        .body("You took too long!")
        .onResponseEnd(ShutdownConnection)
        .build(),
    )
    server.enqueue(
      MockResponse
        .Builder()
        .code(503)
        .addHeader("Connection", "Close")

Shinsuke Sugaya <******@****.***> 1772848386 +0900

            WebApiUtil.setError(404, "Not Found");
            WebApiUtil.setError(500, "Internal Server Error");
            WebApiUtil.setError(502, "Bad Gateway");
            WebApiUtil.setError(503, "Service Unavailable");
        } catch (Exception e) {
            fail("setError should handle various status codes gracefully: " + e.getMessage());
        }
    }

    @Test

          $ref: '#/components/responses/Unauthorized'
        '404':
          $ref: '#/components/responses/NotFound'
        '500':
          $ref: '#/components/responses/InternalServerError'
        '503':
          description: Service unavailable
          content:
            application/json:
              schema:
                type: object
                properties:
                  data:

// //////////////////////////////////////////////////////////////////////
func errBusy(err error) *s3Error {
	return &s3Error{
		code:       "Busy",
		message:    "The service is unavailable. Please retry.",
		statusCode: 503,
		cause:      err,
	}
}

func errUnauthorizedAccess(err error) *s3Error {
	return &s3Error{
		code:       "UnauthorizedAccess",
		message:    "You are not authorized to perform this operation",

   *  * For auth challenges (401: Unauthorized, 407: Proxy Authentication Required.)
   *  * For client timeouts (408: Request Time-Out.)
   *  * For server failures (503: Service Unavailable.)
   *
   * Response header values like `Location` and `Retry-After` are also considered.
   *
   * Client configuration may be used to make follow-up decisions, such as:
   *

		}
	}
	if errors.Is(err, grid.ErrDisconnected) {
		return true
	}
	// More corner cases suitable for storage REST API
	switch {
	// A peer node can be in shut down phase and proactively
	// return 503 server closed error, consider it as an offline node
	case strings.Contains(err.Error(), http.ErrServerClosed.Error()):
		return true
	// Corner case, the server closed the connection with a keep-alive timeout

            return LlmException.ERROR_MODEL_NOT_FOUND;
        }
        if (statusCode == 408) {
            return LlmException.ERROR_TIMEOUT;
        }
        if (statusCode == 502 || statusCode == 503) {
            return LlmException.ERROR_SERVICE_UNAVAILABLE;
        }
        return LlmException.ERROR_UNKNOWN;
    }

    // --- Utility methods ---

    /**

		loadUserCalled = true

		u, ok = sys.store.GetUser(accessKey)
	}

	if !ok && loadUserCalled && err != nil {
		iamLogOnceIf(ctx, err, accessKey)

		// return 503 to application
		return u, false, errIAMNotInitialized
	}

	return u, ok && u.Credentials.IsValid(), nil
}

// GetUser - get user credentials