Trying to setup outbound calls. However i keep getting 'customer-busy' but I even don't see the call on the BYO SIP trunk in my SBC logging. callid= 019a78ca-6736-7ffd-91fe-e9bfeca435ff Timestamp = 2025-11-12 15:58:48.986+00 JSON message = { "assistantId": "588f8e84-432d-4cfc-8824-xxxxx", "phoneNumberId": "dce51408-5a5a-47b7-b51a-xxx", "type": "outboundPhoneCall", "customer": { "number": "+316XXXXXXXX", "numberE164CheckEnabled": false } } Any ideas how to fix this? ps; when i forward an inbound call to VAPI assistant to a PSTN number i see that the calls is sent via the BYO SIP Trunk. ^Marty

Thanks for sharing the details. Since outbound calls show "customer-busy" but do not appear on your BYO SIP trunk, could you confirm if your outbound voice profile is correctly assigned to the SIP trunk and that outbound authentication credentials are set up in both Vapi and your SIP provider dashboard? This will help narrow down if the issue is with routing or authentication. (Reference: [Vapi SIP/Telnyx setup guide](https://docs.vapi.ai/advanced/sip/telnyx)) Source: - [Vapi SIP/Telnyx setup guide](https://docs.vapi.ai/advanced/sip/telnyx)

where can i configure an 'outbound voice profile' in VAPI? I use a BYO SIP trunk. outbound authentication is managed via/on my hosted SBC

Hi Marty, I can help troubleshoot this. Since your outbound calls aren’t even hitting your BYO SIP trunk, it could be related to how the outbound voice profile or routing is configured in VAPI. Just to clarify: are you currently assigning a specific outbound voice profile to your assistant, or relying on the default settings? Once I know, I can guide you on setting it up correctly for BYO SIP trunks. @martyvandeveerdonk

Hi Manja, i'm relying on the default

Since the default profile may not route outbound calls via your BYO SIP trunk, we should set up a dedicated outbound voice profile for your assistant. This ensures proper call routing and authentication through your SBC. Do you want me to guide you step-by-step on creating it, or check your current settings first? @martyvandeveerdonk

If you can help with a step-by-step guide, please. Because I dont see anything related to outbound voice profiles in my VAPI portal

Hi martyvandeveerdonk, If you are experiencing call drops immediately after initiating a transfer, I recommend following the steps outlined in our [call forwarding troubleshooting guide](https://docs.vapi.ai/phone-calling/transfer-calls/debug-forwarding-drops). This guide will help you identify whether the issue lies with your configuration or your telephony provider: 1. Verify forwarding initiation: Use the Vapi API to check if the forwarding was initiated. Ensure the

endedReason

is

"assistant-forwarded-call"

. 2. Check telephony provider logs: Most issues that persist after Vapi's successful forwarding relate to the telephony provider. Access their dashboard using the

phoneCallProviderId

for logs and error details. 3. Network analysis: For SIP calls, download and analyze PCAP files using Wireshark to track transfer requests and responses. If the issue is with SIP transfers, ensure that your configuration follows best practices and that the

phoneCallProviderBypassEnabled

is set correctly according to whether you're using custom call control logic. Ensure your destination number format is correct, the SIP endpoint is correctly configured, and no conflicting settings are present. Use this [additional information about SIP error codes](https://docs.vapi.ai/changelog/2025/5/31) for more accurate error handling. For ongoing issues, ensure your telephony provider's configuration and any forwarding behavior matches your needs.

this issue is related to straight outbound calls. they don't appear on my BYO SIP trunk.

Thanks for sharing the details. Since outbound calls aren’t hitting your BYO SIP trunk, the issue likely involves how VAPI handles default routing versus an explicit outbound voice profile. I can guide you step-by-step in a private session, showing how to configure a dedicated profile, verify SBC authentication, and test the routing to ensure calls flow correctly. When would be a good time to do this? @martyvandeveerdonk

looks as a good plan. can you send a message to marty@anyroute.cloud