Limited Power/Resistance Feedback on Magnus H2 Trainer

Zwift has been working flawlessly with my Magnus H2 trainer for the past 6 months. Since last week, the power/feedback is not working. I noticed that I can spin the trainer in my 52x11 at 100 rpm and it only registers around 250-300 watts. While going uphill in Zwift there is little resistance increase. Essentially it feels like im going downhill on a -20% decline.


  • Power reading in Zwift seems accurate, its like zwift is telling it to reduce the resistance.
  • Trainer difficulty set in the middle (no observed change from easy to hard)
  • ERG mode in the Saris App is working correctly
  • Incline adjustment through Garmin Edge 830 works correctly (i.e. when I dial in 5% the trainer starts to clamp down and it feels accurate)

Steps taken:

  • I have performed multiple spin downs using the Saris App. (everything seems normal).
  • Trainer firmware up to date.
  • Zwift up to date.

Im all out of ideas. Anyone else experiencing this?