I'm seeing this error very frequently when I'm doing consequent calls in a loop with n8n (I'm waiting for call ended signal before proceeding with next one) 1 of every 3 calls give this error. Organization ID: f467a306-b228-4ff1-b4ee-e25f2e70c66c Assistant ID: a20a7d33-bdd1-409e-892a-9280a158ad70 Some Call IDs: - ef7edf47-f0de-4069-bd41-ae7c8d235f49 - e6ea9e4f-2ccf-4510-8fc4-ac185106231e - 0572ac72-1699-470a-bdd3-f9c414c95e27 ... I couldn't find any solution online. I'd appreciate any help. https://cdn.discordapp.com/attachments/1418339958636286112/1418339959114567781/Screenshot_2025-09-18_at_23.56.01.png?ex=69427045&is=69411ec5&hm=439324e235740cc495463bd279898e033c6af71aeb5a666d9c07a617fd08c6d0&

Suggestion: SIP 480 errors often indicate rate limiting or temporary unavailability on your SIP provider's side. Try adding a short delay (e.g., 2–5 seconds) between calls in your n8n loop to avoid overwhelming the provider:

javascript
// n8n pseudo-code
await new Promise(resolve => setTimeout(resolve, 3000)); // 3-second delay before next call

This simple change can help reduce the frequency of 480 errors by spacing out outbound requests. For persistent issues, review your SIP trunk configuration and ensure all required IPs are whitelisted as described in the [Vapi SIP trunk documentation](https://docs.vapi.ai/advanced/sip/sip-trunk). Source: - [SIP Trunking Vapi Documentation](https://docs.vapi.ai/advanced/sip/sip-trunk)

For the call ids you provided, we are seeing this error:

🔵 20:31:14:873 Call `ef7edf47-f0de-4069-bd41-ae7c8d235f49` Waited 300s But Transport Never Connected.
🔵 20:30:27:647 Call `e6ea9e4f-2ccf-4510-8fc4-ac185106231e` Waited 300s But Transport Never Connected.

The call is being initiated on our end, but is timing out due to the phone provider not responding to the request. Please check with your phone provider to see if there are any logs on their side

@User Could you tell, please, why Vapi doesn't send server message with type "end-of-call-report" where occurs error "An error occurred in this call: call.in-progress.error-providerfault-outbound-sip-480-temporarily-unavailable"? Here is example Call id:019a0c4b-4be5-7008-a9cd-8e2cda752471 Assistant id:68b805a7-3723-4a7f-9be6-eca006cbb47f