Elite Derito X trainer problems

I have a rather bizarre problem. When I’m using my trainer it just isn’t remotely realistic. I can’t last more than 15mins in a cat D group ride. I’m
Just burst. In the real world I’m a cat C rider.
It looks like it’s my Zwift sccount that is the problem. I had a friend try my trainer and they are like wow, this is impossible. They then logged in as themself on my trainer and everything is fine. I jump on and it’s super easy.
We looked at the settings on our accounts and there is little difference other than a few kilos in weight.
Does anyone know what could be wrong and how to solve it?
Do I need to delete my account, cancel Zwift amd start again.
Trainer works fine in ERG mode.
I recalibrate regularly, but makes no difference

You might have done this right, but…when you log on and start up your trainer, make sure your trainer is the FEC one not the Real Trainer.
This can make the trainer run with out, or low resistance.