Workflow Activation Error with Telegram Trigger: Undefined 'url' Property

I am following the tutorial to set up the Telegram Trigger with an AI Agent and am using only three nodes. When I try to activate the workflow, I get the error:

Workflow could not be activated: Cannot read properties of undefined (reading ‘url’)

Even when I only include the Telegram Trigger node, the error persists, which leads me to suspect an issue with the credentials. I am unsure which base URL to use. The default seems to connect, but testing the workflow produces another error, and using the URL with [https://t.me/"BOTNAME"] does not work either.

Below is the workflow JSON for reference:

JSONCopied
{  
  "name": "My workflow",  
  "nodes": [  
    {  
      "parameters": {  
        "updates": [  
          "message"  
        ],  
        "additionalFields": {}  
      },  
      "type": "n8n-nodes-base.telegramTrigger",  
      "typeVersion": 1.1,  
      "position": [  
        0,  
        0  
      ],  
      "id": "50b91189-4edb-439a-9553-60c88230d11e",  
      "name": "Telegram Trigger",  
      "webhookId": "fbe0ce65-f533-485b-9bbc-604b19f85a2a",  
      "credentials": {  
        "telegramApi": {  
          "id": "ohwMmiIZNwTj21Tw",  
          "name": "Telegram account"  
        }  
      }  
    },  
    {  
      "parameters": {  
        "agent": "conversationalAgent",  
        "promptType": "define",  
        "text": "={{ $json.message.text }}",  
        "options": {  
          "systemMessage": "Assistant is a large language model trained by OpenAI.\n\nAssistant is designed to be able to assist with a wide range of tasks, from answering simple questions to providing in-depth explanations and discussions on a wide range of topics. As a language model, Assistant is able to generate human-like text based on the input it receives, allowing it to engage in natural-sounding conversations and provide responses that are coherent and relevant to the topic at hand.\n\nAssistant is constantly learning and improving, and its capabilities are constantly evolving. It is able to process and understand large amounts of text, and can use this knowledge to provide accurate and informative responses to a wide range of questions. Additionally, Assistant is able to generate its own text based on the input it receives, allowing it to engage in discussions and provide explanations and descriptions on a wide range of topics.\n\nOverall, Assistant is a powerful system that can help with a wide range of tasks and provide valuable insights and information on a wide range of topics. Whether you need help with a specific question or just want to have a conversation about a particular topic, Assistant is here to assist."  
        }  
      },  
      "type": "[@n8n](/u/n8n)/n8n-nodes-langchain.agent",  
      "typeVersion": 1.7,  
      "position": [  
        220,  
        0  
      ],  
      "id": "9c99ee86-46de-415c-a12d-60249bdc2920",  
      "name": "AI Agent"  
    },  
    {  
      "parameters": {  
        "options": {}  
      },  
      "type": "[@n8n](/u/n8n)/n8n-nodes-langchain.lmChatOllama",  
      "typeVersion": 1,  
      "position": [  
        140,  
        220  
      ],  
      "id": "4c7b7b2c-c6c0-41f5-9f74-bb66e990b4d0",  
      "name": "Ollama Chat Model",  
      "credentials": {  
        "ollamaApi": {  
          "id": "rx6aWfvwf2DmhspH",  
          "name": "Ollama account"  
        }  
      }  
    }  
  ],  
  "pinData": {},  
  "connections": {  
    "Telegram Trigger": {  
      "main": [  
        [  
          {  
            "node": "AI Agent",  
            "type": "main",  
            "index": 0  
          }  
        ]  
      ]  
    },  
    "Ollama Chat Model": {  
      "ai_languageModel": [  
        [  
          {  
            "node": "AI Agent",  
            "type": "ai_languageModel",  
            "index": 0  
          }  
        ]  
      ]  
    }  
  },  
  "active": false,  
  "settings": {  
    "executionOrder": "v1"  
  },  
  "versionId": "95f118ab-762a-4f96-9c28-318b7f8d1360",  
  "meta": {  
    "templateCredsSetupCompleted": true,  
    "instanceId": "bb002afd79a1fde615321eb0dab595c8f1d0f5d342b943a0161a15b5e700e5b3"  
  },  
  "id": "vBT3mLSrTuBhD2Cu",  
  "tags":    
}

Additional n8n setup details:

• n8n version: 1.74.3
• Database (default: SQLite)
• n8n EXECUTIONS_PROCESS setting (default: own, main)
• Running n8n via (Docker)
• Operating system: MacOS Sequoia 15.1.1