I am trying to register my SIP Trunk using a username and password, but it is not working. I enter the credentials, but it does not register on the platform. Even though it says it was registered, it only sends the request by IP instead of sending it authenticated with the SIP username and password. Organization ID: 61d09b13-129f-4353-9eb3-0e7ee89eb6b8

Try this: When registering your SIP trunk, make sure you use the numeric IPv4 address for your SIP gateway and include the

outboundAuthenticationPlan

with your username and password. Here’s an example API payload:

json
{
  "provider": "byo-sip-trunk",
  "name": "My SIP Trunk",
  "gateways": [
    {
      "ip": "203.0.113.10",
      "inboundEnabled": false
    }
  ],
  "outboundAuthenticationPlan": {
    "authUsername": "YOUR_SIP_USERNAME",
    "authPassword": "YOUR_SIP_PASSWORD"
  }
}

Replace the IP, username, and password with your actual details. Using a hostname instead of an IP or missing the authentication plan can cause registration to fail. For more troubleshooting, see the [SIP trunk credential errors guide](https://docs.vapi.ai/advanced/sip/troubleshoot-sip-trunk-credential-errors). Source: - [Troubleshoot SIP trunk credential errors](https://docs.vapi.ai/advanced/sip/troubleshoot-sip-trunk-credential-errors)

I’m trying it this way, but I haven’t been able to register it. On the website, it says the SIP Trunk registration was completed, but when I log into my VoIP platform, it shows that there are no registered users. When I place a call, it goes to the VoIP platform, but with no registered user, as if it were sending the request only to the IP of the SIP platform without actually being registered.

Hi! From what you’re describing, it looks like your SIP trunk is sending calls by IP instead of actually registering with your username and password, which is why your platform isn’t showing any users. I can help you get it properly registered. Can you tell me if your platform has any special authentication settings or port requirements for SIP? That will make troubleshooting much faster. @Rafael

There isn’t any special configuration, and regarding the port, the default setting is 5060. The details are the same ones I am already entering into the platform.

Got it, thanks for confirming. If everything is default (5060, no special setup) and it’s still coming through by IP, then it likely means the trunk isn’t actually registering—just sending traffic. I’ve seen this a few times, and I can help you sort it out properly. We’ll need to check if your VoIP platform is expecting SIP registration or just IP authentication, and how it handles credentials. Which VoIP platform are you using on your side? That’ll help me narrow it down and guide you better. @Rafael

I’m using a VoIP platform called Flux Tecnologia. It uses SIP username and password authentication. @Ramsey

Since Flux requires SIP username/password, the trunk should be sending proper REGISTER requests, not just routing by IP, so we’ll need to dig into that flow. What I’ll do is check the REGISTER attempts, verify if auth headers (Authorization / WWW-Authenticate) are being exchanged properly, and confirm the correct domain/realm and transport settings are being used. I’ll also compare it with how Flux expects the registration to be handled. I’ve handled similar cases before, so I’m confident we can get it working. Feel free to reach out privately and can go through it step by step and fix it quickly. @Rafael

please provide a call id where the auth failed and we will look into it

I can send you the Call ID, but the requests are being sent only by IP instead of using username and password authentication. Call ID: 019d05c0-aac3-799e-93a8-283acdf4e2c3