Hi! I'm in need of assistant. I'm helping a customer to integrate an AI agent to help their clients. This customer has a third party company that does the first calling for them and then transfers the clients (while on the call) to their SDRs. I understood that i need to create a "Free Vapi SIP" in order to be able to receive transfer as a fallback in case all SDRs are busy. The problem is that after i created the Vapi SIP and assign an AI assistant to it, the call never get's through when I try to test with Linphone. It just keeps calling for ever.

Suggestion: Make sure your SIP provider (or Linphone) is forwarding inbound calls to the correct Vapi SIP URI and that you have allowlisted the required Vapi IP addresses. For example, your SIP URI should look like:

sip:YOUR_PHONE_NUMBER@sip.vapi.ai

Also, ensure these IPs are allowlisted: - 44.229.228.186/32 - 44.238.177.138/32 This step is crucial for inbound calls to reach your Vapi AI assistant successfully ([see documentation](https://docs.vapi.ai/advanced/sip/sip-trunk)). Source: - [SIP Trunking Documentation](https://docs.vapi.ai/advanced/sip/sip-trunk)

I don't see any "registered" in the sip settings. Can it be a matter of waiting for it to be online? If so, how do i check it or how long it usually takes? As for the assistant, i'm using the standard ones (Riley) first to test it

Hi O_XiNDa, If you're integrating your Plivo SIP trunk with Vapi, here's a quick guide to set it up for inbound and outbound calls: Outbound SIP Trunk Configuration 1. **Plivo Console Setup**: - Go to

Zentrunk (SIP) → Outbound Trunks → IP Access Control List

and create a new IP group. - Add IP addresses

44.229.228.186/32

and

44.238.177.138/32

. - Create a new outbound trunk and select your IP ACL. 2. **Vapi Configuration**: - Use the API to create a credential with your Plivo termination SIP domain. - Associate your Plivo number with this credential for outbound routing. Inbound SIP Trunk Configuration 1. **Plivo Console Setup**: - Go to

Zentrunk (SIP) → Inbound Trunks → Origination URI

and create a new URI with

sip.vapi.ai;transport=udp

. - Configure the inbound trunk using this URI and attach your Plivo number to the trunk by selecting Zentrunk as the application. 2. **Vapi Configuration**: - Create a new inbound SIP credential using Vapi API. - Link your Plivo number with this credential. For detailed procedural steps and commands, you can refer to our [Plivo SIP Integration guide](https://docs.vapi.ai/advanced/sip/plivo). Additionally, make sure that your Plivo account and SIP configuration meet all prerequisites to avoid issues with connectivity or call routing. If you're troubleshooting dropped calls or transfer issues, review our [debug guide on forwarding drops](https://docs.vapi.ai/phone-calling/transfer-calls/debug-forwarding-drops) for detailed steps.