No refresh token when using Passwordless/OTP grant through SMS

Hi ,

I have been trying to get Passwordless work using SMS OTP (Using Twilio for the same). This is my request…

https://xxx.us.auth0.com/passwordless/start

{
“client_id”: “xxxxxxxxxxxxx”,
“connection”: “sms”,
“phone_number”: “+91961…”, //set for connection=sms
“send”: “code” //if left null defaults to link
}

This gives back a 400 bad request. I have looked at the documentation and this seems to be good. Anyone has faced this kind of issue before??