Telegram openaı http node eror400 404 issues

[Mustafa]

Hi n8n team,

I’m building an AI-powered Telegram automation on n8n Cloud using:

Telegram Webhook → Edit Fields → OpenAI (LLM) → HTTP Request

My goal: When I send a message to my bot, OpenAI generates a reply, and it’s sent back to Telegram.

Setup:

1. Webhook Node

   • URL: https://mmussto.app.n8n.cloud/webhook/telegram-input
   • Status: Working
   • Telegram messages arrive correctly.

2. Edit Fields Node

   • Produces JSON like:
     {
     “chatId”: 6039014854,
     “userMessage”: “Merhaba”
     }

3. LLM (OpenAI)

   • Using basic LLM node with my OpenAI key
   • Input: {{ $json[“userMessage”] }}
   • Output: response is OK (no error)

4. HTTP Request Node

   • Method: POST
   • URL: https://api.telegram.org/bot<MY_TOKEN>/sendMessage
   • Body (JSON):
     {
     “chat_id”: {{$json[“chatId”]}},
     “text”: {{$json[“llmOutput”]}} // or raw message for testing
     }
   • Headers: Content-Type: application/json

Problems:

• I still get:
  • 400: Bad Request: message text is empty
  • Or 404 Not Found
• Even when using hardcoded text like “text”: “Hello test” → still fails
• But the same API call works outside n8n
• The OpenAI LLM node gives correct output (I checked manually)

Tried:

• New Telegram token
• Rebuilding flow twice
• Both Fixed & Expression modes
• Manual test with cURL (worked)
• Setting webhook manually via BotFather (succeeded)

What I Need Help With:

• Why does the HTTP node not send the Telegram message?
• Is there a bug with the value mapping from LLM to HTTP node?
• Is there something specific I must do in n8n Cloud to pass the correct body?

Thanks for your time.
Mustafa

n8n.io - Workflow Automation

Describe the problem/error/question

What is the error message (if any)?

Please share your workflow

(Select the nodes on your canvas and use the keyboard shortcuts CMD+C/CTRL+C and CMD+V/CTRL+V to copy and paste the workflow.)

Share the output returned by the last node

Information on your n8n setup

• n8n version:
• Database (default: SQLite):
• n8n EXECUTIONS_PROCESS setting (default: own, main):
• Running n8n via (Docker, npm, n8n cloud, desktop app):
• Operating system:

[darrell_tw]

@Mustafa

• 400: Bad Request: message text is empty
• Or 404 Not Found

400 and tell you the message text is empty

{
“chat_id”: {{$json[“chatId”]}},
“text”: {{$json[“llmOutput”]}} // it means here the output {{$json["llmOutput"]}} is empty
}

So the LLM output might not meet your expectation.

---

404 is werid about the url is not found.

 https://api.telegram.org/bot<MY_TOKEN>/sendMessage

should be fixed. Can you confirm

---

Please provide the workflow code instead of giving the n8n workflow url. We can not see the workflow directly.