Telegram OpenAI HTTP Node Errors (400/404)

Hi callin.io team,

I’m building an AI-powered Telegram automation on callin.io 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 callin.io
• 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 callin.io Cloud to pass the correct body?

Thanks for your time.
Mustafa

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