WebRTC create call

Hello, I have a question related to creating a call
I did everything step by step https://developer.goto.com/guides/GoToConnect/17_HOW_makeAndReceiveCallsUsingDevicesAndCallsApi/ and after creating the device, the greetings message appears in the channel as described in the instructions, also after create device extensions it gives the status 201 for the extension number, but "make a call" still gives 409 error