Bug Zwift speed


In advance, sorry for my broken English.
I have been having a speed issue on Zwift for some time with my Tacx Flux.
The speed is unrealistic, I can do flat courses by doing 18/20kms per hour when before at the same time I was doing a classic distance +/- 30kms.
I tried logging in on my iPad, then on a MacBook Air, no change. Also I disabled the rest of the devices in Bluetooth.

Do you have a solution ? I thought of an Ant+ key but this would itself be connected via an intermediate cable, my devices not having USB ports.

Thanks for your help, have a nice day!

Help me, please !

Hi @Benoit_Muselet

Welcome to the forum.

Zwift will calculate your speed based on your power number.

Did you try to recalibrate the trainer using the Tacx software?

did you change your weight or height in the game recently?