Tacx vortex connects in Tacx app but no power/mph registering when I try to calibr

Hi,

trying to setup a vortex a friend gave me…

  • using Tacx app on iphone
  • connects instantly 
  • go to calibrate
  • no mph/power registered, sticks at 0
  • try to connect to Zwift and trainer is not showing at all

Any ideas?

thanks in advance,

Ed