Power dropping

[morite]

I have a Drivo and use it via ANT+ to zwift

I am having an issue that I can't seem to resolve......

When doing a workout in Zwift it will tell me to increase power to 250 watts. I spin up and get the power to 250w but when I try to hold it the power starts to drop by 70w-80w, to 170w-180w, and then I struggle to get it back up, as soon as I do and try to hold the same happens.

I have tried different ways to spin it up. increasing the rpm in the same gear, changing the gear up a couple and keeping the rpm the same, slowly building the power, etc all have the same results. I watched the speed and rpm go up but the power still goes down.

It is even worse in ERG mode. when the power drops the resistance increases and that makes me pedal slower which then increase the resistance more until it gets to the point that Zwift de-activates ERG before I can pedal again.

Has anybody seen this or have any solutions/suggestions?