Zwift Run pod not showing speed on iPhone app

Dear all,

I just bought the zwift runpod to run on zwift. To test the run pod I tried to link it trough the zwift app to my iPhone. This is succesfull, but the pod does not transmit any speed to zwift. It already tried fresh batteries and to reset the pod by removing the battery. This did not have any succes. When I insert the battery, the pod flashes two times with a red light. Does anyone have any idea what might be the problem why the pod does not work?

Thanks a lot for your answer!

Kind regards,