Cadence error tacx vortex smart

Hi guys,

I am using my Tacx Vortex smart for 9 months and lately, the Cadence is’nt right anymore. It’s pretty stable at the beginning of a session ans then goes from 1 to 150. Sometimes it stays between 10 and 60 even if i pedal around 100… This is really annoying…

I’ve tried the Tacx calibration but the zwift one did not work the zwift app was not able to calibrate…

Can someone help me here ?

Thanks!