How long is that short period you have to wait until successfully get your next call forwarded? Can you reproduce the problem consistently with the same calling pattern?

This is weird. I test over and over again to forward incoming calls to an extension and it works every time. Here is how I handle an incoming call to extension 102, forward the call to extension 103 using the forward API in Node JS.

subscription.on(subscription.events.notification, function(msg)

    console.log("======");

    if (msg.event.indexOf('telephony/sessions') > 0){

      var body = msg.body

      //var callerNumber = body.parties[0].from.phoneNumber

      if (body.parties[0].direction == "Inbound" && body.parties[0].status.code == "Setup"){

        console.log(JSON.stringify(msg));

        forwardCallByExtensionNumber(body, '103')

        }

    }

});



async function forwardCallByExtensionNumber(call, extensionNumber){

  var endpoint = '/restapi/v1.0/account/~/telephony/sessions/'

  endpoint += call.telephonySessionId

  endpoint += `/parties/${call.parties[0].id}/forward`

  console.log(extensionNumber)

  console.log(endpoint)

  try{

    var resp = await platform.post(endpoint, {

      extensionNumber : extensionNumber

    } )

    var jsonObj = await resp.json()

    console.log(JSON.stringify(jsonObj))

    console.log("FORWARDED")

  }catch(e){

    console.log(e)

  }

}