I recently upgraded to OS 10.15 Catalina. Since then I cannot open Parallels Desktop 15. It is saying that I need an activation key. I have been upgrading for the last several years, so when I go back to the last full purchase and use one of the activation keys supplied (multi-user subscription) it tells me the key is associated with another account. I only have 1 account. I have gone online and cannot find a way to retrieve or deactivate/reassign an activation key. Any thoughts on how to resolve?