It's a little hit and miss. I think you need to damage something first before you try and turn it on.
If you try, get a failure, then damage something, and try again it won't work and you'll need to reboot the game and trainer.
I have around a 70% sucess rate with it working. So there is definately something iffy with that option, just not sure exactly what.
i just tested it again and it works fine for me, i played the game for a few hours and not a single error popt up. like the user above me said, try to hit a few things first, maybe get some damage first, then try to use the options.
Install .NET CORE v3.1 from Microsoft.
I already have tried to do that and it didn't change anything... Is what I would say if I didn't Install the wrong program like an idiot. I installed asp net core instead since that was the first .net core 3.1's I saw on the page. I thank you for correcting me and for your timely response.