When trying to add a SIP trunk, i see the error message "Couldn't validate SIP trunk credential. SIP gateway creation failed." if "inboundEnabled": true. If I set "inboundEnabled": false, the trunk and numbers can be created. But I am unable to receive an incoming call. Note: My provider is not able to forward calls to a SIP URI like YOUR_VIRTUAL_NUMBER@sip.vapi.ai.

I can help you fix this SIP trunk setup so inbound calls work smoothly without SIP URI forwarding. The issue likely comes from how your provider handles authentication when inbound is enabled. Can you confirm if your provider supports IP-based authentication or only username/password registration? @Jörg

Hi @Vercel My provider supports IP-based authentication for inbound.

Thanks for confirming that. Since your provider supports IP-based authentication, I can help you set it up so inbound calls work smoothly. Let’s talk privately, and I’ll walk you through the setup step by step. @Jörg

Hi, to configure the SIP Trunk, please follow the documentation for whitelisting the IP addresses: Then use this template as a guide to configuring both inbound and outbound gateways. The inbound gateway will need a static IP address and the outbound gateway will use the resolved domain name using UDP protocol:

{
  "provider": "byo-sip-trunk",
  "name": "My SIP Trunk",
  "gateways": [
    {
      "ip": "sip.provider.com",
      "port": 5060,
      "outboundEnabled": true,
      "inboundEnabled": false,
      "outboundProtocol": "udp"
    },
    {
      "ip": "203.0.113.10",
      "port": 5060,
      "outboundEnabled": false,
      "inboundEnabled": true
    }
  ]
}

Once you have configured the SIP trunk, you will receive a value for credentialId. Save that and use it for the next step of assigning the SIP trunk to a phone number, as that is a required value for setting up the phone number. If you encounter any issues with the setup, please feel free to reach out.

I am not getting it to work... these are the options that I have with my provider for inbound. I tried adding the VAPI IP adresses, but the calls are not connected. https://cdn.discordapp.com/attachments/1425022707543707678/1425770634968956969/image.png?ex=68e8cbe0&is=68e77a60&hm=fa853c74fc822f70cfed759114f8b75262e767a42b843411fb0b2c3dbb053088&

We apologize for the delay in responses lately. We are in process of making some changes to our workflow in how we handle support requests. The good news is that we are starting to get back on track of having a 48 hour response time and we would like to start cleaning up anything old. With that being said, just wanted to check in with you to see if you have made any progress or changes to your project since support has last reached out.