How many scenes can I have open at the same time?

in V-ray with a single license I could have work many different scenes at the same time.
Now, with Corona, I can work in a single scene: is it correct?
Is it a way to solve this problem?

Thanks!

AFAIK there’s no limit how many instances of 3ds Max with Corona you can have open on a single PC with a single license.

for example, if I open two scenes, in the first one I haven’t problem, the second one I can’t use it because appears the error message “licence busy” or similar something

I don’t think that’s expected behaviour. I’d suggest you to open a support ticket about that at Chaos help portal: https://support.chaos.com/hc/en-us/requests/new