// to retry with 503 errors when server is coming up.
			return auth.Credentials{}, false, ErrServerNotInitialized
		}

		// Check if the access key is part of users credentials.
		u, ok := globalIAMSys.GetUser(r.Context(), accessKey)
		if !ok {
			// Credentials could be valid but disabled - return a different
			// error in such a scenario.
			if u.Credentials.Status == auth.AccountOff {