Hey team, I'm having an issue with outbound calls where the call connects and rings, but the AI never speaks. Here's what's happening: The Issue: - Call goes from

queued

→

ringing

→ connects - After Twilio trial message plays, there's a 3-4 second silence - Then call drops with "Customer Did Not Answer" or transport error - The AI never gets a chance to say the first message What I've tried: - Removed duplicate greetings from system prompt - Switched between "assistant speaks first" and "user speaks first" modes - Used both

phoneNumberId

and raw Twilio credentials - Verified Twilio Account SID and Auth Token are correct - Phone number is active and configured in Vapi Setup: - Using Twilio integration (trial account) - Outbound calls via API connected through n8n - Assistant has

firstMessage

configured - Call status shows as

ringing

in API response but never progresses to

in-progress

Call logs show: - Status:

ringing

then times out - "Customer Did Not Answer" (but I'm answering the call) - Sometimes:

call.start.error.get.transport

I've attached screenshots of: 1. Call logs showing the error 2. Assistant configuration 3. API response showing call status Is this a known issue with Twilio trial accounts? Or is there something wrong with my transport configuration? Thanks! https://cdn.discordapp.com/attachments/1424035047639482500/1424035048784531456/Screenshot_from_2025-10-04_18-20-37.png?ex=68e27b7c&is=68e129fc&hm=2d96b8b32bf53ad1fd84ddfe0fed0292d7e5b516bbff1ef06a5024bd80ff8903& https://cdn.discordapp.com/attachments/1424035047639482500/1424035051045261552/Screenshot_from_2025-10-04_18-22-57.png?ex=68e27b7d&is=68e129fd&hm=b36c7d6f76afd3a1a5ba88ec4d5d2d21472143160f4643cffad0e84037543c09& https://cdn.discordapp.com/attachments/1424035047639482500/1424035051590385744/Screenshot_from_2025-10-04_18-24-03.png?ex=68e27b7d&is=68e129fd&hm=b1d79a78ff71fc1c8f6b473b87e1b38e5853f83afcd10a310b78ee997bb493b0& https://cdn.discordapp.com/attachments/1424035047639482500/1424035052349685780/Screenshot_from_2025-10-04_18-24-33.png?ex=68e27b7d&is=68e129fd&hm=c0158b61a45c4204e875bc6ba684f641a299f435317f51f770b19f4e17ea825e& https://cdn.discordapp.com/attachments/1424035047639482500/1424035053020909731/Screenshot_from_2025-10-04_18-54-53.png?ex=68e27b7d&is=68e129fd&hm=f8743be264c1579891b6341a2dfb86a3bcee21c557425f536ca2b7058e124f68&

Suggestion: Double-check that your API request includes both a valid

assistantId

and `phoneNumberId`—missing or incorrect values for these fields can cause the AI not to speak, even if the call connects. Here’s a sample JSON body for the API call:

json
{
  "assistantId": "your-assistant-id",
  "phoneNumberId": "your-twilio-number-id",
  "customer": { "number": "+1XXXXXXXXXX" }
}

Make sure these IDs match the ones configured in your Vapi dashboard. This is a common cause of silent calls and transport errors according to the documentation and community support. Sources: - [Discord Community Support Example](https://discord.com/channels/1211482211119796234/1370485222214336564) - [Vapi Outbound Calling Documentation](https://docs.vapi.ai/phone-calling/outbound-calls)

Message marked as helpful by @GIDEON! 🎉

I have included the correct assistant and phone number IDs and have retried serveral times but still facing the issue, would it be due the structure of the json in the htt[p request to vapi?

It isn't working cause your location has probably been considered high risk calling numbers on their geo-permissions setting. I can help you solve this if its urgent.

Oh, okay I'll try the workflow on other numbers with US extensions. Yes Gideon, I'd very much appreciate any help from your end, pls let me know if you need any info regarding this.

Message my DM, I would create a loom video explaining it..