sign extension doesn't work

[bigcatln]

I used to sign my extension with sketchup online tool, I did it just a few weeks ago successfully, but today I failed all the time for the same extenstion that I signed before successfully, I made a very simple plugin with starndard structure like myplugin.rb, myplugin folder, and mypluginmain.rb in the folder, but it also fail, I think the Sketchup team may altered their tool ,but I can't find any information on web. anyone knows why?
thanks

[TIG]

It was flaky last week, when drag-n-drop of the RBZ didn't work on some specific OSs, but then navigating to the RBZ file and selecting it would still work...
I'm surprised it's not been properly fixed by now.