Hello otomo,
If you haven't used Spine in a while, please know you'll need to download and reinstall Spine from your license page, else it can't reach the server due to a certificate expiration. Sorry for the trouble! We have ensured this problem won't happen again. Please head to your license page to redownload the installer and reinstall Spine, this should fix the problem.
In case you still encounter problems, I'll be happy to help!
