Hi Nate,
I try to unistall and reinstall Spine with my license number, I try to start Spine on another computer and same popup.
I don't understand why it doesn't working anymore
EDIT :
Acutally, it's working now :o !
I just update the spine.exe and everything is alright.
So I uninstall spine, restart my PC, download Spine.exe from my personnal license's link, launch the spine.exe from my desktop, and it's work fine, I'm so glad