Why do the Ollama AI node and Telegram webhook fail in n8n across Docker and Windows setups?

Below is an explanation and step-by-step guide addressing both issues:

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1. Ollama AI Node Connection Issue

Why it happens:
The Ollama node is designed to work with a locally hosted Ollama instance. When you run n8n in the cloud or inside a Docker container, using a URL like http://localhost:11434 points to the local network inside that environment—not your computer. This means n8n cannot “see” the instance running on your physical machine, resulting in an ECONNREFUSED error.

How to resolve it:

• On Cloud:
  • Since n8n Cloud runs remotely, it cannot access your local machine’s localhost. To use the Ollama node successfully in this environment you’ll need to either host Ollama in a publicly accessible network or run both services together on the same host.

• With Docker:
  • If you run n8n inside Docker and your Ollama instance is on your host machine, you cannot use localhost because it refers to the container itself.
  • Instead, configure your Docker container so that n8n can reach the host. On Linux, you can add the host IP in the container, or use Docker’s special DNS name host.docker.internal (which works automatically on Docker Desktop for Windows/macOS).
  • For example, update your [Ollama credentials URL] in n8n from

  • http://localhost:11434
    to
  • http://host.docker.internal:11434
    This directs n8n (inside Docker) to your host machine where Ollama is running.

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2. Telegram Webhook Error: HTTPS Required

Why it happens:
Telegram requires an HTTPS webhook URL. When you’re running n8n locally (or even in Docker) without a reverse proxy handling TLS (HTTPS), the webhook URL remains HTTP. Telegram then rejects the webhook with the error:

  Bad Request: bad webhook: An HTTPS URL must be provided

How to fix it – Step-by-Step Guide:

1. Set Up a Reverse Proxy with SSL Termination:
   Configure a reverse proxy (for example, Nginx, Caddy, or Traefik) in front of your n8n instance. This proxy will handle incoming HTTPS connections and forward them as HTTP to n8n.

2. Obtain a Valid SSL Certificate:
   You can use Let’s Encrypt to automatically obtain a free SSL certificate for your domain.

3. Configure the Proxy:
   For example, with Nginx your configuration might include:

   NGINXCopied
   server {
     listen 443 ssl;
     server_name yourdomain.com;
   
     ssl_certificate     /path/to/fullchain.pem;
     ssl_certificate_key /path/to/privkey.pem;
   
     location / {
       proxy_pass http://localhost:5678;  # assuming n8n runs on this port
       proxy_http_version 1.1;
       proxy_set_header Upgrade $http_upgrade;
       proxy_set_header Connection 'upgrade';
       proxy_set_header Host $host;
       proxy_cache_bypass $http_upgrade;
     }
   }

4. Configure n8n's Webhook URL:
   Set the WEBHOOK_URL environment variable for n8n to the public HTTPS URL. For example:

   SHELLCopied
   export WEBHOOK_URL=https://yourdomain.com/

   Ensure that this URL is the one used in your Telegram credentials and webhook configuration.

5. Restart n8n and Your Reverse Proxy:
   After updating the settings, restart both n8n and your reverse proxy so that the changes take effect.

6. Test the Webhook:
   Use the “Test workflow” or “Test step” button in n8n to verify that the Telegram Trigger now accepts the HTTPS webhook without error.

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Summary

• Ollama AI Node:
  • The ECONNREFUSED happens because localhost inside a Docker container or on the cloud does not match your local machine where Ollama is running. Use host.docker.internal (or host networking) so n8n can reach your Ollama service.
  • Alternatively, host Ollama in the same environment as n8n for a more direct connection.

• Telegram Webhook Issue:
  • Telegram requires an HTTPS endpoint. Set up a reverse proxy with SSL termination and configure the WEBHOOK_URL environment variable to point to your HTTPS address.
  • Ensure your Telegram bot is registered with this HTTPS webhook URL.

Implementing these changes should resolve the connectivity issues for both the Ollama node and the Telegram webhook across your different environments.