Im following this guide https://docs.vapi.ai/advanced/sip However after creating a sip phone number its not possible to call my agent, i have tried exactly as the guide says using linphone

Remove the

serverUrl

from your SIP phone number in vapi, ensure an

assistantId

is set, and dial

sip:your_username@sip.vapi.ai

from Linphone without registering or using credentials, just direct dialing..