Telegram openaı http node eror400 404 issues

Questions
1

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.

:white_check_mark: Setup:

  1. Webhook Node

  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

:cross_mark: 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)

:magnifying_glass_tilted_left: Tried:

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

:red_question_mark: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

Describe the problem/error/question

What is the error message (if any)?

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2

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.