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VAPI•2mo ago
static-pink

URGENT: BYO SIP Trunk Connection Error

Hi Vapi support team,

I'm trying to connect Vapi to Biztel, a Japanese number service provider, via SIP trunking, but the connection failed. Please help me.

The configuration is as follows:

  1. Create a SIP trunk credential in Vapi
curl --location 'https://api.vapi.ai/credential' \
--header 'Content-Type: application/json' \
--header 'Authorization: Bearer MY_VAPI_PRIVATE_KEY' \
--data '{
"provider": "byo-sip-trunk",
"name": "Biztel Trunk",
"gateways": [
{
"ip": "s202218044035.u.biztel.jp",
"inboundEnabled": false
}
],
"outboundLeadingPlusEnabled": false
}'

The SIP server address "s202218044035.u.biztel.jp" is provided by Biztel, and they have no authentication during SIP connection.
The DID is like “617801”, so I set outboundLeadingPlusEnabled = false

  1. Associate a phone number
curl --location 'https://api.vapi.ai/phone-number' \
--header 'Content-Type: application/json' \
--header 'Authorization: Bearer MY_VAPI_PRIVATE_KEY' \
--data '{
"provider": "byo-phone-number",
"name": "Biztel SIP Number",
"number": "617801",
"numberE164CheckEnabled": false,

"credentialId": "928a3834-172f-4efd-a412-8989a9f226f9"
}'

  1. Inbound call test
The SIP connection is also configured on the Biztel side. When calling the Biztel phone number, it routes to the SIP address: "sip:617801@sip.vapi.ai"
But the SIP connection failed. The SIP response received from the SIP INVITE is "486 Busy Here". I tried several times, still the same.

Please check the configuration to see if it's correct or if there's something I'm missing.

Thank you for your help.
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