Hello I created a Free VAPI SIP uri to set up call forwarding from my phone number to an agent. I linked the agent to this SIP and tried to make a call. The call was not accepted. My phone support said that this address rejected the call. Help me figure it out. SIP sip:qksmfptdmxe@sip.vapi.ai and ID f1f48cba-4d89-4142-8cfd-9f9870f4d0b9

Hi there! 👋 I see you're having trouble with your Free VAPI SIP URI rejecting calls. While I can't determine the exact reason why your specific SIP URI (sip:qksmfptdmxe@sip.vapi.ai) is rejecting calls without seeing error logs, I can definitely help you troubleshoot the most common issues. Here are the most likely reasons your VAPI SIP URI might be rejecting calls: ### Authentication Issues VAPI expects authentication credentials in the Authorization header. The username must be your SIP username (qksmfptdmxe), and the password can be anything except the keyword "test" according to the [documentation](https://discord.com/channels/1211482211119796234/1211483291191083018/threads/1334238882660618250). ### Configuration Problems Make sure you've properly linked your agent to the SIP URI. This requires: 1. Creating a SIP phone number using the

POST /phone-number

endpoint 2. Including your

assistantId

in the request body 3. Using the correct format for your SIP URI:

sip:qksmfptdmxe@sip.vapi.ai

Here's an example of the correct configuration:

json
{
    "provider": "vapi",
    "sipUri": "sip:qksmfptdmxe@sip.vapi.ai",
    "assistantId": "your_assistant_id"
}

### Network Configuration Verify that your network allows SIP traffic and that any firewalls are configured to allow SIP messages to pass through. SIP ALG (Application Layer Gateway) settings could be interfering with the SIP messages according to [troubleshooting information](https://discord.com/channels/1211482211119796234/1211483291191083018/threads/1334919245468799007). ### SIP REFER Handling Confirm that your system is set up to handle SIP REFER messages, as Vapi uses SIP REFER to transfer calls according to [documentation](https://discord.com/channels/1211482211119796234/1211483291191083018/threads/1336713212233515089). ### Free VAPI SIP Limitations Be aware that Free VAPI SIP has some limitations: - Free phone numbers can only make calls to US and Canada - Limited to 10 outbound calls per day

Your call may have been rejected due to incorrect SIP URI format, authentication issues, unregistered endpoint, or misconfiguration recheck your Vapi call logs and SIP settings.

Thanks for the reply. I just tried to set up a call via Zoiper and it worked. But for some reason my telephony can't do it.. Maybe you can look at the detailed logs for this sip uri and I will provide them with the data what is the problem? SIP sip:qksmfptdmxe@sip.vapi.ai and ID f1f48cba-4d89-4142-8cfd-9f9870f4d0b9

Is this for the inbound call?

Yes sir