Minoura B60R Wattage Issues

Im doing workout using trainer Minoura B60R…In the workout activities i have to ride up to 628watt / 107 rpm…

The problem i already to up to 400++watt and suddenly the wattage drop to 300++(Cadence still maintain /increase) 

Anyone got same issue as me? :( 

Seem Classic trainer not compatible anymore with zwift. 

It sounds like you’ve outgrown your trainer.

The Minoura B60R is only designed to hit the upper 600w range on the trainer’s high resistance setting, which Zwift isn’t calculated for. On the low resistance setting (the only setting Zwift virtual power is intended for), you’re going to see a much lower wattage ceiling due to the limitations of the calculations/trainer.

If you’re really at a point where your workouts are that intense, you should probably look at either a different trainer or a power meter to get the most out of your rides.