for some reason it stopped working for my site... even after I created new key ? please advice?
and I use to had few other keys and now I don't see them in the download keys page?
Yes, this is caused by an update in Let's Encrypt SSL certificates on hosts. And Joomla using outdated certificate checks.
The fixes for this have been merged into Joomla. But Joomla will have to release a new version, and you will need to update, before this all starts working again.
it sucks and is completely out of my control.