n8n-io/n8n · error

Method Not Allowed

Error message

Method Not Allowed

What it means

Error "Method Not Allowed" thrown in n8n-io/n8n.

Source

Thrown at packages/@n8n/nodes-langchain/nodes/mcp/McpTrigger/McpServer.ts:273

	async handleDeleteRequest(req: express.Request, resp: CompressionResponse): Promise<void> {
		const sessionId = this.getSessionId(req);

		if (!sessionId) {
			resp.status(400).send('No sessionId provided');
			return;
		}

		const transport = this.sessionManager.getTransport(sessionId);

		if (transport) {
			this.pendingCallsManager.cleanupBySessionId(sessionId);

			if (transport instanceof StreamableHttpTransport) {
				await transport.handleRequest(req, resp);
				return;
			}
			resp.status(405).send('Method Not Allowed');
			return;
		}

		resp.status(404).send('Session not found');
	}

	getSessionId(req: express.Request): string | undefined {
		return (req.query.sessionId ?? req.headers['mcp-session-id']) as string | undefined;
	}

	getMcpMetadata(req: express.Request): { sessionId: string; messageId: string } | undefined {
		const sessionId = this.getSessionId(req);
		if (!sessionId) return undefined;

		const message = jsonParse(req.rawBody.toString());
		const messageId = MessageParser.getRequestId(message);

		return { sessionId, messageId: messageId ?? '' };

View on GitHub (pinned to 5ac6606e81)

When it happens

Trigger: Thrown at packages/@n8n/nodes-langchain/nodes/mcp/McpTrigger/McpServer.ts:273 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of n8n-io/n8n@5ac6606e81 (2026-08-12). Data as JSON: /api/errors/6d4a0b4de4548fc3. Report an issue: GitHub.