old licence disapiered after licensing new C

I have WinXP running Cubase Studio4, for years, working as it should …
on the other comp, iMac 10.13.6, I installed yesterday Cubase Artist 10.5, purchased as a upgrade to aforementioned Studio 4
after installing&licensing, on USB dongle,
I cant start Studio 4 (on XP), it’s license disappeared not only from the dongle but also from my Steinberg account
Have I done something wrong or what?
I’m a full-time pro musician and in the middle of a project, so this is utterly unacceptable …
Help please


Samuel Sacher