n8n-io/n8n · error · Error
Not authenticated — call login() first
Error message
Not authenticated — call login() first
What it means
The N8nClient.cookie getter returns sessionCookie for SSE auth, but throws if it was never set (no login). This is a fail-fast guard so SSE callers don't silently send requests with an undefined cookie and get 401s deep in the stream.
Solutions
- Call await client.login() before reading client.cookie.
- If reusing a client across a long lifespan, re-login when the cookie is missing.
- Guard callers with `if (!client.isAuthenticated) await client.login()`.
Example fix
// before: const sse = new SseClient(client.cookie, ...); // after: await client.login(); // const sse = new SseClient(client.cookie, ...);
Defensive patterns
Strategy: validation
Validate before calling
if (!client.sessionCookie) await client.login(); const cookie = client.cookie; // safe after the guard
Prevention
- Treat login() as a mandatory precondition for any cookie consumer.
- Add an isAuthenticated accessor to make the check ergonomic.
- Re-login on long-lived processes when the cookie may expire.
When it happens
Trigger: Constructing an SSE client and reading `client.cookie` before calling login(); reusing a client after its session expired without re-login.
Common situations: Forgetting to login; refactoring that bypasses the login step; long-running processes whose cookie was cleared.
Understand the failure class
- Authentication and authorization failures — expired tokens, bad credentials, and missing scopes.
Related errors
- SSE connection failed
- Could not determine personal project ID
- Failed to authenticate with n8n — no session cookie received
- Invitation accepted but no session cookie received
- MCP api-key rotate endpoint returned a redacted key —…
AI-assisted analysis of n8n-io/n8n@5ac6606e81 (2026-08-12).
Data as JSON: /api/errors/848de6538a370898.
Report an issue: GitHub.
Appendix: source
Thrown at packages/@n8n/instance-ai/evaluations/clients/n8n-client.ts:991
});
}
// -- SSE helpers ---------------------------------------------------------
/**
* Build the SSE events URL for a given thread.
* Used by the SSE client to open a streaming connection.
*/
getEventsUrl(threadId: string): string {
return `${this.baseUrl}/rest/instance-ai/events/${threadId}`;
}
/**
* Expose the session cookie so the SSE client can authenticate.
*/
get cookie(): string {
if (!this.sessionCookie) {
throw new Error('Not authenticated — call login() first');
}
return this.sessionCookie;
}
// -- Internal fetch ------------------------------------------------------
private unwrapRestData<T>(result: unknown): T {
if (result && typeof result === 'object' && 'data' in result) {
return (result as { data: T }).data;
}
return result as T;
}
private async fetch(
path: string,
options: { method?: string; body?: unknown; timeoutMs?: number } = {},
): Promise<unknown> {
const headers: Record<string, string> = { 'Content-Type': 'application/json' };View on GitHub (pinned to 5ac6606e81)