n8n-io/n8n · error

500

500

Error message

e.message

What it means

Returned as HTTP 500 `{ code: 500, message: e.message }` from the AI Assistant `/chat` (or stream-style) endpoint when an error occurs BEFORE streaming begins (headers not yet sent). The catch asserts `e instanceof Error` then sends the native message. If headers were already sent, it just ends the response to avoid a double-write.

Source

Thrown at packages/cli/src/controllers/ai.controller.ts:136

							role: 'assistant',
							type: 'error',
							content: streamError.message,
						},
					],
				};
				res.write(JSON.stringify(errorChunk) + STREAM_SEPARATOR);
			} finally {
				// Clean up event listener
				res.off('close', handleClose);
			}

			res.end();
		} catch (e) {
			// This catch block handles errors that occur before streaming starts
			// Since headers haven't been sent yet, we can still send a proper error response
			assert(e instanceof Error);
			if (!res.headersSent) {
				res.status(500).json({
					code: 500,
					message: e.message,
				});
			} else {
				// If headers were already sent dont't send a second error response
				res.end();
			}
		}
	}

	@Post('/chat', { ipRateLimit: { limit: 100 } })
	async chat(req: AuthenticatedRequest, res: FlushableResponse, @Body payload: AiChatRequestDto) {
		try {
			const abortController = new AbortController();
			const { signal } = abortController;

			const handleClose = () => abortController.abort();
			res.on('close', handleClose);

View on GitHub (pinned to 5ac6606e81)

Solutions

1. Check the server logs for the full stack trace of the underlying `e`.
2. Verify AI provider credentials and connectivity from the n8n host.
3. Update `@n8n/ai-assistant-*` packages to a version compatible with the SDK.
4. Retry — transient provider 5xxs are common.

try { await api.post('/ai/...', payload); } catch (e) { if (e.response?.status === 500) { logAiConfigDiagnostics(); await retryWithBackoff(); } else throw e; }

When it happens

Trigger: The upstream AI SDK fails during request setup (auth, payload validation, network DNS, model unavailable) before any chunk is streamed; an unexpected throw inside `aiService` prior to the first `res.write`.

Common situations: AI provider outage; misconfigured AI credentials (`N8N_AI_*`); SDK version mismatch; request payload triggers an internal assertion.

Related errors

• output.error.errors[0]
• Plan lacks license for this feature
• 401
• User is missing a scope required to perform this action
• error.message

AI-assisted analysis of n8n-io/n8n@5ac6606e81 (2026-08-12). Data as JSON: /api/errors/71149b599fd75f74. Report an issue: GitHub.