nats-io/nats-server · warning

could not fetch <%q>: no response

Error message

could not fetch <%q>: no response

What it means

URLAccResolver.Fetch treats a nil HTTP response with no error as a fatal anomaly. http.Client.Get normally returns either err or a response; a nil response with nil err is unexpected, so the resolver reports it as 'could not fetch <url>: no response'.

Source

Thrown at server/accounts.go:4251

		MaxIdleConns:    10,
		IdleConnTimeout: 30 * time.Second,
	}
	ur := &URLAccResolver{
		url: url,
		c:   &http.Client{Timeout: DEFAULT_ACCOUNT_FETCH_TIMEOUT, Transport: tr},
	}
	return ur, nil
}

// Fetch will fetch the account jwt claims from the base url, appending the
// account name onto the end.
func (ur *URLAccResolver) Fetch(name string) (string, error) {
	url := ur.url + name
	resp, err := ur.c.Get(url)
	if err != nil {
		return _EMPTY_, fmt.Errorf("could not fetch <%q>: %v", redactURLString(url), err)
	} else if resp == nil {
		return _EMPTY_, fmt.Errorf("could not fetch <%q>: no response", redactURLString(url))
	}
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusOK {
		return _EMPTY_, fmt.Errorf("could not fetch <%q>: %v", redactURLString(url), resp.Status)
	}
	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return _EMPTY_, err
	}
	return string(body), nil
}

// Resolver based on nats for synchronization and backing directory for storage.
type DirAccResolver struct {
	*DirJWTStore
	*Server
	syncInterval time.Duration
	fetchTimeout time.Duration

View on GitHub (pinned to 3a66a489d2)

Solutions

1. Use the default http.Client or a correctly-behaving transport for the resolver
2. Inspect any custom RoundTripper for paths that return nil response and nil error
3. Log and restart/reconnect if a transient transport corruption is suspected

Example fix

// before
ur, err := NewURLAccResolver(url) // replaced client with custom transport returning nil,nil
// after
ur, err := NewURLAccResolver(url) // keep default client, or fix RoundTripper to always return non-nil resp with err

jwt, err := fetchAccount(resolver, key)
if err != nil && strings.Contains(err.Error(), "no response") {
    // replace/recreate the resolver client; use fallback resolver
}

When it happens

Trigger: Calling Fetch when ur.c.Get returns (nil, nil) — a pathological client/transport state, e.g. a custom HTTP client or RoundTripper misbehaving.

Common situations: Custom HTTP client injected into URLAccResolver (NewURLAccResolver with custom client) whose transport violates the net/http contract; heavily customized/proxied transports.

Related errors

• could not fetch <%q>: %v
• will only fetch valid account keys
• store operation not supported for URL Resolver
• delete must be enabled in server config
• not self signed

AI-assisted analysis of nats-io/nats-server@3a66a489d2 (2026-09-02). Data as JSON: /api/errors/2f40a8d723eeae19. Report an issue: GitHub.