Error 11200 : unable to fetch response URL between n8n & Twilio

Questions
1

Hi,

Before starting i should say that i am quite new and making this AI agent for the first time related to travel information . My AI agent is fetching all the required data from google sheet for sending the same through whatsapp chat.

My work flow is success when i execute the flow manually but it is not getting automatically triggered. I have contacted both n8n and Twilio,

Twilio has identified the issue: they’re getting “Error 11200 - unable to fetch response from URL” when trying to call my webhook, even though manual curl requests work fine.

Twilio’s Diagnosis:

This indicates a connectivity issue between Twilio’s servers and n8n cloud, specifically:

  1. SSL certificate issues (invalid or self-signed certificate)

  2. Firewall blocking Twilio’s IP ranges

  3. Access restrictions on the n8n cloud instance

  4. Response timeouts beyond 15 seconds

I need help in this urgently, i am stuck with this and need to fix this urgently.

Regards

Sunny

3

Thnx for your message. I have been trying to get the help from n8n but even for the paid account they are not been doing any help. Can you tell me how can i check the following at my end as suggeted by you.

  • Checking that the webhook URL is using a valid public SSL cert (no custom/self-signed certs

  • Verifying there are no IP restrictions or security settings blocking Twilio traffic on the n8n instance.

I am really sorry for being ignorant in all this and appreciate your kind help. My project is stuck only because of this.

Regards

Sunny